/diy/ - Do It Yourself

this thread's digits brought to you in part by the venerable MC68030

>>1512041
d-decap it

>>1509125
Looks like a chinese knockoff, to me.

>>1512042
if you want to see more, DM @NXP for their private insta

>>1512046
How could you possibly keep track of your construction?

>>1512068

>>1512069
Does kicad do PCB-less autorouting?

>>1512047
hue

Is there a minimum grid size for typical PCB fab? I.e. if I move a pad over x mils, at what value for x is the fab house going to give me the exact same board?

>>1512201
I guess it would be the minimum division their CNC can take.

>>1512072
lol no
you're looking for something more like IC design software

>>1512201
no, they won't generally promise you anything other than a board that passes electrical tests
it never hurts to read a board house's capabilities page, and perhaps compare it with other houses' capabilities pages

I wasn't sure if the back of the 230v diode was live or not so i measured AC potential between the heatsink and the AC wires connected to the white chocolate powering the led, and one read about 66V and the other read about 85V

the fuck?
It was supposed to be either 0V or 230V

>>1512235
Capacitive coupling, if you tie it with a ~20kΩ resistor to ground it should drop right down to 0V. If you're worried, try a 1MΩ and 230kΩ to ground and see if the voltage changes compared to just your (presumably) 10MΩ DMM.

Also you should be grounding the -ve side of the switching converter anyway (since if you're getting capacitive drift it's going to be isolated), and what the fuck is that unholy power resistor?

>>1512236
The resistor reduces the fan speed so it's not like a Boeing is flying over me every time i turn on the light
grouding is not really needed (not to mention it would require me to buy new 3 wire cables with the large 3 point plugs) since the light is not going to be touched. I just wanted to know if i can touch it while it's on, while i'm testing it and working on it
guess i'll better be on the safe side and not touch it while it's on

>>1512237
Touch it now, faggot.

>>1512238
I am. Since it's unplugged.
I am maybe not book inlegittent but i am hood smart

>>1512239
>inlegittent
I hope that was intentional

I asked >>1511755 last thread about antenna design. >>1511786 recommended me the practical antenna handbook by joseph j. carr.

If someone can answer me some basic / more basic questions I'd be really grateful.

1. Can I use two different antennas? So one that is less efficient and one that is more efficient (the target frequency is within both antennas bandwith obv).

2. Can i use a directional antenna and a omnidirectional antenna as well?

3. I understand that as a rule of thumb a bigger wire for a monopole antenna (or dipole antenna) means I have more bandwith. Do I loose efficiency for that? Or is it just upsides without the downsides?

Thanks for helping me out.

>>1512266
>Can I use two different antennas?

of course. consider pic related vs the size of your radio

> Can i use a directional antenna and a omnidirectional antenna as well?

they both use radio waves, so yes.

> big wire question

I don't know.

>>1512274
I am not quite sure why I did not think about that. It's so obvious that you can and yet I didn't consider it. Thank you very much for that already!

Since it's going to be used for telemetry on a rocket the rocket antenna has to be smaller, have less weight and sturdier than the ground unit. Again thanks a lot.

>>1512266
Somehow I doubt the bandwidth of the antenna is going to be a problem, but the beamwidth can be. It's on a rocket; can you really aim it properly?
You can use more than one antenna, but in this case it would probably make sense to have just one somewhat directional antenna pointing downwards and have your more directional antennas on the ground, where you can aim them to the rocket more easily.

Btw, hams like antennas. You might want to ask them: >>1484287

>>1512278
There's a lot of prototyping to be done first. The first prototype with a reusable 2kN engine and a functional control loop should be done in about 2 years. So far the rocket basically has a omnidirectional antenna, the ground unit is going to be directional. As soon as our recovery system is fully functional in determining apogee I can start aiming the beam of the rocket "down".

Thanks a lot for the idea to ask the hams, I completely forgot about them.

>>1512201
The gerber file is fixed precision, usually 1/0.1/0.01mil, called 2:3/2:4/2:5 format.

>>1512281
>>1512297

>>1512266
>I asked >>1511755 last thread about antenna design. >>1511786 recommended me the practical antenna handbook by joseph j. carr.

>The things I have no idea about:
>1. Will a less efficient antenna in the rocket (dipole w/ reflector etc) bottleneck? Or can I use a bad antenna to send and use a very efficient one to recieve the (worse) signal?
The only thing that counts is the link budget, how much data you can get through. Use a simple antenna on the rocket and a more elaborate n the ground station and you are fine.
>2. Does a Yagi-Uda antenna make sense? Or do I want to use a dipole antenna with a reflector?
Yagi on the rocket is unlikely to be good since it will extend into the air stream. You want a conformal antenna.
>3. where do I look at a practical guide? I'm interested in application, less in theory (unless I need it to understand obv)
In addition to the book you got recommended you could also look into free space infrared communications.

>If someone can answer me some basic / more basic questions I'd be really grateful.
>1. Can I use two different antennas? So one that is less efficient and one that is more efficient (the target frequency is within both antennas bandwith obv).
Yes. Deep space probes use this, so can you.
>2. Can i use a directional antenna and a omnidirectional antenna as well?
Yes. A relatively simple conformal dipole on the rocket and a more high gain directional antenna on the ground makes sense. Just keep in mind that a directional antenna gives good gain in the main lobe but low gain outside.
>3. I understand that as a rule of thumb a bigger wire for a monopole antenna (or dipole antenna) means I have more bandwith. Do I loose efficiency for that? Or is it just upsides without the downsides?
No. Long antennas are used for longer wavelengths that have narrower bandwidth.

You need to think about bandwidth and distances required.

>>1512068
It's easy. You don't hope around like some spaz from component to component and do each connection deliberately and purposefully

>>1512308
>Yagi on the rocket is unlikely to be good since it will extend into the air stream. You want a conformal antenna.
I was more thinking about it for the ground. I'm looking into conformal antennas though.
>you could also look into free space infrared communications
on it. Thanks.

>You need to think about bandwidth and distances required.
I'm trying to, it's just hard until the propulsion crew knows if their liquid engine can actually produce the required thrust.
Do you mean bandwidth as in "range of frequencies" or as in "data transmission rates"? Either way, I'll try to guesstimate it soon.

Thanks a lot for such an in depth answer, I at least know where I need to look and what I need to look for. "antenna design" is just hard to overlook and understand what is needed when.

>>1512351
>Do you mean bandwidth as in "range of frequencies" or as in "data transmission rates"? Either way, I'll try to guesstimate it soon.
Bandwidth is number of bits per second.

>>1512030
being more specific this time, how does the current and voltage regulation work in this power supply?

>>1512359
Isn't it from some utoob video? Why don't you check what the faggot who drew that mess says?

Anyway, the return current (+ output -> your load -> - output) causes a voltage drop of I*R + 0.6V in the R2-D1 combination. Q4 compares an adjustable fraction (P2+R5) of that to its Vbe of 0.6V. If current and thus the voltage drop is too high, it pulls current away from Q2 and Q3, turning Q1 off.
The voltage limit uses similar logic, but Q5 compares a scaled and offseted fraction of the output voltage against its Vbe of 0.6V. The extra transformer, D6, D7, C1 and R1 produces a -8.2V voltage used in the bottom side of the P1-R4-R3 voltage divider. This way the comparison is (mostly) against that relatively stable -8.2V, instead of transistor's rather unstable Vbe. It also allows higher loop gain and thus better regulation.

MOSFET drain source breakdown voltage, is it typically assumed to be the RMS or peak?

I have an IRFZ44N whose max VDS is listed at 60V but it survived 92V pulses at 280kHz with a 10% duty cycle.

>>1512358
not always, http://www.antenna-theory.com/basics/bandwidth.php uses it differently. That's why I asked.

>>1512392
it's peak. semiconductors have statistical deviance on ratings like that. the listed rating might be a few deviations down from the actual average breakdown voltage of one of those mosfets.

My board design to use up all the unused mosfets I have looks like this. What do you think? I need to cram the components up a bit better in order for the signal connector to fit in. I'm using transistors to drive the optocouplers, but I need to?

>>1512516
why R5 and R21? if you do need R5 then i'd flip it to improve isolation. also if you put the LEDs on the input side then you can have shorter power trace lengths. i'd also expand the power traces to occupy all available space for marginal thermal improvements.

>>1512579
R1 is a pulldown, R5 is to limit the current going through the opto transistor, I think

>>1512581
i meant R21 rather than R1. R5 isn't needed for current limiting because of R1.

i would also consider isolating all four output channels since the redundant screw terminal pins are already there and it'll allow for h-bridges and the like.

>>1512584
>h-bridge
There's already a module for that with a proper H-bridge IC, this is more aimed at people wanting to drive a led strip or a small heater.

That R21 is a pulldown, but now I got rid of that transistor and also made it into a 2 channel board since I can have them for 20 cents each and do away with more of my components. I have 30 pc817 and 30 50n06, this way I can order 15 boards and empty two of my drawers.

I'll try a different routing to see if I can make it single-sided.

>>1512516
i would have put the transistors much closet to the connector and everything else up north.
you don't seem to need 5 12v pins on the connector but more ground pins would make routing easier...
are you going single layer to make this yourself or you just enjoy challenges? cost a dual layer from china it's the same price probably.

>>1512390
I am so fucking grateful for your comment man, thanks. I've been trying to understand how this works and I couldn't find anything about this circuit online, and the youtuber who did the video just talks about its construction. I am reading your comment 100 times if that's necessary to finally understand the circuit

https://www.youtube.com/watch?v=cTqjepPQMgA

Anyone know what's causing the vertical "bleeding" effect on this OLED display?

I assume from the way it looks that something is staying partially charged when switching rows. But I've tried fiddling with the driver chip's "precharge/discharge time" and a few other settings, with no effect so far. The only thing that seems to help is drawing a vertical line somewhere on the screen, which for some reason reduces the effect enough to be almost unnoticeable.

Display module datasheet: http://www.newhavendisplay.com/specs/NHD-2.23-12832UCB3.pdf
Driver datasheet: http://www.newhavendisplay.com/app_notes/SSD1305.pdf

>>1512663
Same thing but with vertical bars on the edges. You can still see some bleeding on the camera but it's almost invisible IRL. I assume having pixels lit up elsewhere on the row is helping it discharge properly?

>>1512390
My take on things is that it's not about the gain (if at all) but the temperature drift of Q5, which is the _only_ reference. The Z-diode does not act as reference because it is not in series with the base-emitter junction.

The 8V2 Z-diode has about +5mV/K and the Vbe of Q5 has a Tc of about -2mV/K. Acting together this can reduce the temperature drift of the output voltage, especially at higher values because of the divider effect:
30V/0.6V=50 and 50*-2mV/K=-0.1V/K. If the machine warms up by 20°C (which isn't much), the output voltage would decrease from 30V to about 28V without Tc compensation.

Some more Z info: The Zener effect (Vz<~5V) has a negative Tc while the avalanche effect (Vz>~5V) shows a positive Tc. Z-diodes between ~5V and ~6V have a very low Tc because both effects act concurrently. Z-diode is the conventional term for such diodes, no matter which breakdown mechanism dominates.

Apart from all that, the construct has a severe design flaw: the size of the mains transformer T1. 30V*4A=120W but 24V*3.5A=84W. Normally you dimension the transformer to 1.5*Pout because of the additional I^2*R losses caused by the non-sinusoidal current that has to charge the storage capacitor (after the bridge) with relatively short high current pulses. T1 should have 180W instead of 84W or at least a thermo switch to prevent a disaster, housefire in memespeak.

>boss wants to buy an expensive electronic gadget
>say i can diy the exactly same thing for 10% of the price if he is willing to wait a month for the plane to land
>says yes
>parts arrived
>assemble thing
>bringing it to work tomorrow to show him

i checked all the connections and resistor/cap/ic values and the code and shit like 10 times and it works flawlessly, but i fucking bet my ass when i plug it in tomorrow at work it will fucking start smoking and he will be like "great work anon you're fired."

>>1512674
What is the gadget in question?

>>1512674
is he going to pay 90% of the price as a bonus

How old were you when you first started getting into circuitry, /ohm/? I'm just now starting to get the basics down after wasting my early twenties being a drugged-out degenerate. I wish I had started sooner! There are so many awesome things I want to make.

>>1512703
weebs are not people

>>1512266
You wouldn't be sending a frog into space, would you?

Probably isn't the best place to ask, but thought i'd post anyway.
https://moderncombatsports.co.uk/products/rechargeable-refillable-12g-co2-cylinder
Can I refill this kind of cartidge with ordinary air? I want to use it to power a pneumatic artificial muscle.

>>1512687
Anon got JEW'd

>>1512731
>You wouldn't be sending a frog into space, would you?

french person, anon. frog is derogatory.

>>1512742
You wouldn't get much kick out of it if you did. Those things store the CO2 as a liquid (I think) thanks to the high pressure, though I'm unsure if normal air can do the same. Look at a phase diagram and see if the condensation pressure at room temperature is greater than the maximum pressure those cartridges can take. But in general I think you'd have a hard time doing so since such a high-pressure compressor would be somewhat exotic.

I'd like to see any calculations on energy stored per mass of high and low pressure air cans however, so if you do test them feel free to post them here.

new to circuits, r8 my full adder(in progress)
doing this pleases my autism
the carry is inverted but werks, just have to make a 3way xor now
how did people even design all the gates anyway? random transistor combinations?

What are the best T12 tips clones?

Also, is there any EU website where I can purchase the Hakko genuine ones?

>>1512731
Not yet. The next 3+ years are planned to get there so I'll focus on that first.

>>1512742
I don't think that will work for your purposes. You would be better off using a central air tank and routing from that. Paintball stores can probably get you a decent deal.
You may also want to try hydraulics instead.

>>1512751
>doing this pleases my autism

it would please our autism, and you might get some replies, if you posted your circuit.

>>1512767
hope this helps

>>1512789
https://www.youtube.com/watch?v=waEC-8GFTP4

>>1512795
what do you mean

>>1512717
Rude

>>1512703
when i graduated at 21 (not EE). i started designing functional circuitboards at 23. still, about half of them don't work in some capacity due to lazy oversights. designing a functional product is a lot of work and revisions.

how to roll tiny inductors on tiny cores without these fuckers springing up??

>>1512863
Use some sort of machine or ratchet to hold the spindle and reel to stop them from unwinding? Add epoxy as you go?

>>1512863
the way they solve springback in manufacturing is just to bend the object slightly more than desired. so you could wrap the coil onto a slightly smaller cylinder. you're not going to do the math or find/make an optimal diameter cylinder though so that might be hard to do in practice.

a little air gap won't hurt you though. the flux fringing should be marginal. so you could just hot glue or epoxy the coil assembly together if you wanted.

>>1512703
At 18 I made a "little gem MK2" amplifier and it was so god damn horrible (but it still worked) I pretty much forgot about it until 26 or 27, when I got an Arduino. I wanted to prototype my stuff and bought a plastic laminator and a lot other stuff I stopped using when I found out about the chinese pcb houses.

BTW, remembering about the Little Gem MK2 made me want to make a series of modules for people to solder and put inside a sheet metal case and bolt that sheet metal case to a MDF or plywood cabinet, all open-hardware, but with the PCB's made in China and resold by me. The first model would be something like the Marshall and Fender miniamps, but with a decent PCB and a laser cut MDF cabinet for a 6" woofer (which I have somewhere). I imagine a practice amp with a opamp drive section with empty pads on the feedback loop so people could experiment with different diodes an components, easily make their own unique amps ( I have a prototype of this too, btw)

OrCAD is a piece of shit, what to use instead?

>>1512886
ZenitPCB

>>1512894
seems kinda obscure, is it easy to get parts libraries for it?

>>1512896
thatsthejoke.jpg

Is there such thing as a variable reference voltage IC that I can use with an op amp in order to check if different li ion packs still have enough charge? I.e, if I add a small trimpot I can set tune it for 3, 4 or 5 cells

>>1512920
I'm guessing a 1.8v zener diode and a trimpot to divide the voltage from the battery itself would work

>>1512742
You can, but you won't fit much in before reaching the pressure limit.

what servos should i get to make an armor bearing exoskeleton?

>>1512896
It was a joke. Personally I use LTspice for simulation, and would probably use KiCAD for drawing schematics if I was in the business of making PCBs that aren't just permanent marker lines on a piece of dirty copperclad.

>>1512936
I'd use hydraulics myself, the holding power would be very useful for not requiring current to be expended while standing still. Arguably you could do something similar by shorting out the windings of your servos, but it's a lot more work and would still probably require gearing, since electric motors tend to move far faster than hydraulics. Though I suspect that's just because hydraulics are far easier to get extremely low speed:force ratios from out of the box.

>>1512894
How many people do you think lurk on this thread? When I see something like this it makes me think there's maybe five dudes posting and answering questions that people drop by and ask

>>1512984
>there's maybe five dudes
probably
t.one of those dudes

What is the best way to take DC voltage and transform it into an audio current to a speaker? Is it a VCO and if so, what is the simplest VCO to make for this application? If not where should I be looking?

>>1512999
the one that gives the results you want
>Is it a VCO
probably, followed by a speaker amp
>what is the simplest
probably this one
http://learningaboutelectronics.com/Articles/Voltage-controlled-oscillator-VCO-circuit-with-a-555-timer.php

>>1512663
Are those Final Fantasy Tactics numbers?

>>1512984
To be fair it was just last thread. Also you're probably correct, if I had a trip everyone would frequently say "oh not you again". More than 1 in 8 of the posts on this thread are mine.

>>1513003
It's https://fonts.google.com/specimen/Cormorant, traced over to make a bitmap version. I guess FFT used a similar looking font?

>>1512703
I soldered together a simple constant current driver for a TCDCS device when I was 17 or so. I would've made an AM radio transmitter earlier if I had the money for parts. Technically I had a 200-in-1 Radioshack kit, but I didn't have any clue what I was doing.

https://www.amazon.com/Maxitronix-200-in-One-Electronic-Project-Lab/dp/B0002AHR04

When I was 5-7, I was being babysat at a house where they had an electronics kit, a more simple one.

21 I think when I started Engineering at CC, so 21 or 22 when I took the first circuits class.

Only in uni after we covered more of the theoretical and hard applications of transistors/amplifiers/etc did I get more into it. 27 was my senior project, trying to drive a .5-1.5 MHz sine wave, ~300V RMS, relative to a neutral line, into a load which varied between 7000 and 50 ohm. In 5-10ms. I went through so many damn designs.

>>1512789
But anon

1+1+1 = 1 + carry. In your circuit, the led turns off.

>>1513002
An important thing: If the control-voltage-pin impedance is greater than maybe 10k ohm, you want a buffer, because there is a 2/3rds VCC reference something impedance on the control voltage pin. Going extra distance, you can attach an active filter so the pulse train is converted to sinusoidal. Active because different frequencies mean a simple filter won't work.

>>1513005
Thank you for replying

>>1513005
>FFT
that means "fast fourier transform" round here, buddy

>>1513013
You uncultured swine.

>>1513015
can i use this to convert DC to AC

>>1513015
Isn't that closer to a triangle wave than a sine? I'd use that 2-transistor LCR oscillator that popped up a few threads ago instead.

>>1513017
Sort of, but I wouldn't use it to power anything. It would be like powering a load with a linear regulator, somewhere between 1/2 and like 4/5 of the power your circuit uses will be turned to heat within the output buffer. A proper sinusoidal inverter will use a switching converter outputting a cleverly varying duty cycle paired with a low-pass LC filter, which is fairly similar to how a class-D amplifier works.

>>1512703
barely out of diapers. I was seduced by Popular Electronics cover art in the supermarket
it was in high school where I first started learning what the hell I was doing, thanks to the wacko guy on the BBSes who was a retired electronics engineer and just happened to live right down the street in the housing projects behind the strip mall. he gave me my first scope and a ton of components

>>1513021
>closer to a triangle wave than a sine?
https://en.wikipedia.org/wiki/Wien_bridge_oscillator
The version in the image has no automatic gain control (AGC) to prevent clipping, you have to do it manually.

About to solder for the first time, just some basic ground wire to a pot surface. Any beginner tips on what I will most likely fuck up? I know that I'm supposed to tin the solder iron tip, as well as the surface and the wire.

>lets into oscilators
>make collpits because people say that it`s the easiest, most reliable etc
>does not oscilate
ok

>>1513088

1. read the OP comment
2. there is no 2

>>1513095
Thank you.

>>1513092
>simplest
that's news to me

>>1513088
>pot surface
Guitar pot. Took me ten minutes to look up what the hell you meant.

>>1513117
Honestly you can make a simple one with an op-amp or ring oscillator. Obviously if you want more consistent behavior (voltage speaking) or flexibility it needs to be better designs.

What do you say?

I am making a pair of custom 128x64 consoles with one pre-programmed game (bomberman) with network communication with eachother using nrf24l01. That way you just turn them on and play instantly.

>>1513144
3d-printed body

>>1513144
Schematic in KiCad

>>1513147
Can you switch off these childish crayon colors in kidcad?

>>1513149
If you weren't a brainlet and knew how to use the application, you'd know the answer.

>>1513149
Here, just 4u

>>1513168

CRAYON COLORS REEEEEEEEE

>>1513168

>>1512238
Do a flip faggot!
And then grab the mains

>>1512674
Please grab a spycam and record for epic lols

>>1512703
I remember the moment vividly. For some reason my autistic ass had a flashlight for a favorite toy. Dropped it down the stairs. Dad told me to get 2 toilet paper tubes and tape and we cobbled together a hillbilly mag light.

I absolutely refuse to learn to code tho. I cheated in school. Never learned how to type numbers or symbols properly. Kek

>>1512731
Please say yes

>>1512742
Sure. Be sure and put a T in it so you can bleed off water.

>>1513220
>spycam
unfortunately the only one i own is currently installed inside of a locker room for our female staff

>>1512744
The only thing better than a /diy submarine.

4channel space program launch when?

>>1513228
Gg

Anyone here use "inline" meters like these in their projects for monitoring fluctuations? I need something like the upper one that combines volt, amp, and watt outputs I can read at a glance. I'd be using it mostly for manual energy generation. Basically, hooking it up to a crank/pedal, small wind turbine, small hydro turbine, even solar panels, and similar energy generation systems to monitor the output of the system. The unit would be part of a charging system that many varied types of power inputs can be plugged into.

I only need info from people who have actually used these and are familiar with them. Like what not to do or what their best use is in such a system, if possible. Thanks.

>>1513252
waiting for my usb power meter from ebay (~$5 shipped), says its good for 0-30v, up to 5A. shows time, power, volts, current. i'll probably crack it open and connect it to a battery/brick so it isn't powered off the source

I once saw an educational video from Texas Instruments which said something like that an open-collector (or -drain) output can be converted into a push-pull output with a buffer and a resistor. This supposedly saves a considerable amount of power (no pull-up resistor needed). Is this true /ohm/?
Pic related

>>1513291
Sure, why wouldn't it be? Device out 0, buffer out 0, no current.

are there any obvious grave mistakes i should avoid with (screw-) terminals?

i got a new freezer and the whole electrical wiring in my kitchen is just wonky as fuck, i moved here somewhat recently and i only saw the wiring in its full glory today for the first time. the place hasnt burned down so far so i thought i'd just leave it as it is and pray regularly but idk

layout looks like pic related, none of the terminals seem to get warm with all of the devices running, so that's good ... i'll prolly get a smoke detector for that room so when the whole place goes up in flames i'll at least be awake to watch it and maybe vacate the premises in a timely manner

>>1513343
> 0. Electrics ≠ electronics. Mains wiring goes to /qtddtot/ or /sqt/. PC assembly to >>>/g/.

>>1513350
oh okay, thanks. sorry, first time posting here.

>>1513291
The two inverters form a bistable circuit. Once it has been switched to zero by the o.c. output it will stay in that state till kingdom come. That's why the logic IC is called HC666.

ah heck i just realised that joule thief is a pun on jewel thief

I've been trying to setup this rgb light bulb from gearbest, it's an "Utorch LE7 E27", the problem is it won't connect to the app, since it just blink in red light, I've tried everything the support said, and it still won't work, and there isn't any customer service nor info about it on the internet so, what else could I do?
I've already
-checked the router so it's 2.4 ghz
-reseted the bulb 1000 times (it lights up, I just can pair it with the app)

The phone can find it but just not connect, which I've tried several times, the app that came with bulb was efamilycloud, which is basically the same as smart life and tuya smart, anything I couls try?

>>1513620
>what else could I do?
have you tried unplugging it and plugging it back in?

>t_24hr_helpdesk

>>1513092
no idea why they would have told you such a thing. I have never, not even once, been able to get one of those to start
Pic related is a design due to the late Neil Heckt based on a fast comparator (typically LM311) providing positive feedback. it starts reliably and the oscillating frequency is the 1/(2*pi*sqrt(L*C)) one would expect

>>1513175

>>1513570
... damn

/diy/ help me. I have a master's in electrical engineering and work as an rf/antenna engineer and I want desperately want to get into playing with electronics as a hobby. The problem is that I have no project ideas. Not a single one.
Any advice?
I have an oscope, dc power supply, and an LMAOwavetek function generator..
Rpi and arduino as well.

>>1513645
top

>>1513720
(good) hams love to home brew. get a license that'll let you onto bands 10m and longer and there will be many opportunities to make things
weird clocks are a some-time favorite. make it receive your region's time/frequency broadcast for extra fun

>>1513720
that's kinda back asswards, how'd you make it through a masters in EE without having any personal interest in electronics as a hobby?
the best way for you to get project ideas is to find a problem in your life and solve it with electronics.

Anyone know about modding/improving tv's?

The top of the image on flat screen is fucky when it handles a signal from a NES or SNES over composite, but if I put trick it to treat it as component it handles it fine. Every now and then the whole screen shakes a little when it's correct for a few frames. It also doesn't do this with a 480 signal like from the game cube or N64.

I'm hoping it's a timing issue from a crystal with the wrong frequency or something.

Thoughts on what I should look into to fix this?

> pic related, it's the top right corner of the title screen for super mario world

>>1513252
I use those mini 2- and 3-wire voltmeters all the time. (if you're paying 7.95 for those you are getting ripped the fuck off)
they don't usually come very accurate so you have to make sure to calibrate them (there's a pot on the back for that). once calibrated they seem to be very linear and don't drift.
that big power meter one if I'm not mistaken does NOT have a calibration pot. there are a bunch out there based on pretty much the same board that are all similar with different features. none of them can be calibrated.
I used this one, pic related, recently. no calibration but it was dead on balls accurate from the factory, and one of few that can read tenths of a milliamp. sold by DROK on amazon.

>>1513749
That's the TV trying to deinterlace a 240p signal, the proper workaround for that to get good results is buy one of the retro friendly scalers such as the RetroTink2X

>>1513252
I use one of the top style ones to measure 12V shit around my desk, accuracy was fine out of the box, wouldn't be great for hand crank/pedal measurement as it's not that fast updating, for solar/hydro/wind it'd be fine so long as you can maintain that minimum ~6V.

>>1513748
how to get a gf with electronics

I'd like to attach a composite connection to this TV, but it does not have a composite in. It does have a composite out connector. Normally it gets its video from radio. Is this possible?

>>1513840
Here is a picture of the board the antenna was connected to. The connector at the bottom used to go to the CRT main board. I can't find a diagram or a pinout online. I suspect one of these pins holds composite video signal. Is there a way to verify?

How does a vending machine tell that a bill is not a fake and discern its value?

>>1513841
There is likely a composite out underneath the RF module. Look up the modules part number and get a pin out.

>>1513858
This is not /sqt/ shit dick.

I want to connect 2-3 80mm computer fans from a single power source, namely 12v 1a wall socket adapter.

I guess it should be in parallel but what resistor should I put in the beginning, for safety, right after the power jack and the power switch? The fans will be probably 12v and around 0.1 to 0.2a each.

It'll be my first project to solder myself, do anons of ohm have any other advice?

>>1513926
slight update, I got an even smaller adapter; an old nokia 5v 350ma would that suffice? The fans don't have to operate with a full power, but I don't want the power supply to burn.

>>1513931
the fans may not manage to spin at all with a 5v supply. your 12v supply will be fine. the resistor is unnecessary. you're operating it within its ratings. just don't short anything.

>>1513926
No resistor, just put them there. you can test them with a multimeter to see how much current they draw at nominal voltage, then see if the power supply can handle that.

>>1513624
Ofc I have, still won't work

>>1514121
be happy nsa has one less source of information on you

>used to go to school 13 years ago where we did some electronics stuff
>used to hate it and be bored as fuck with it
>13 years later get into electronics again
>love it now, do it in my free time as a hobby
>using a roll of a 13 year old solder i had left over from school days
i wonder what teenage me would think if he could see his future self. Would probably think i am a loser. Would probably be right.

This little ac/dc cunts are completely isolated and floating right?
So if i feed 230v into one side it's completely save to touch the wires coming from the 5V DC side right?

>>1514207
Yes. Transformers isolate the secondary circuit from ground. Murphy's law sais nothing is completely safe, but I'd trust it if it was in an enclosure where a loose screw or something wouldn't bypass the transformer.

>>1514213
I really hope the chinks didn't forged to put the kapton tape between the two windings or some shit like that

>>1514207
Would really need to have more detailed photos of module, but generally it looks to be isolated - has optocouplers, bias winding, no clearly visible tied ground.

But I would not trust this device where there is any chance of touching operating device. Isolation implementation is a joke I even wonder why they bothered creating isolated AC/DC module in the first place.
Clearances/creepages are a joke, no safety devices of any kind on AC side.
On top of that it is quite likely to fail conducted emissions as well and I don't need that shit but this is just personal grudge.

>>1514225
don't worry, kapton tape would probably be too expensive for them

>>1514228

most of what you just posted is hogwash.

>>1512030
New guy here, is there a pastebin for soldering iron recommendations?

I have in a project in mind but would be starting from scratch in terms of material/tools.

>>1514281

1. google, as in pic related
2. buy a hakko fx 888d like i did. it's great.
3. buy what the other guys suggest later on in this thread

>>1514287
>>1514281

lots of guys do not like the push buttons to set the temp, and prefer a knob. I can see their point of view. I don't know the p/n for the knob version.

>>1514200
son, am proud

>>1514228
can confirm, they use Koptan® tape. that said, I bought a roll of it and it seems fine
>conducted emissions
so solly, rine firter is customer responsibirity

>>1514281
I've been very happy with Pic related

>>1514293
>>1514296
>>1514287
I'm still in college so dropping $100 on something I'll only use a couple times a year at best (assuming I don't get sucked into the hobby for some reason) is a bit of a stretch.

Is it worth getting something cheaper if you only plan on using it once or twice? Or is anything less than $100 just catch-your-house-on-fire tier?

I see a Weller WES51 for $85 on Amazon which is still a bit up there but slightly more affordable and the $12 saved would go a long way in terms of project materials.

Ok goys, I know ya missed me. I think I have my next project in mind.

Found these work light LEDs that are made for trucks or ATVs whatever vehicle you want to stick em on. But I don’t want them to be attached to a vehicle, I want them to be portable. The package says 1 Amp for the lights, but I’m still not sure if that’s for one light or both combined.

So I have this 12V-3A power supply that could power them off a 120V outlet. But of course I want to make it battery powered too, so I have this on-off-on switch and could either string up some 18650s or use an old AGM battery from my scoot. AGM would be easy to recharge from a battery charger. Not sure how to charge the Li-Ions though if I use those. Would the 12V power supply even charge the 3x18650s? Makes me want to keep an eye out for a discontinued 12V power tool battery charger and sacrafice that for the cause.

Besides being a dumb waste of time and money, is there anything I’m doing totally wrong?

>>1514309
>just catch-your-house-on-fire tier?

it's not that. the cheap shit works well the first day and then gets worse every time you use it. you can see from pic related that I was a very slow learner.

>>1514309
temperature regulation is a must if you don't want to ragequit the hobby
how about a "908D" setup? https://www.aliexpress.com/item/YIHUA-908D-60W-Electric-Soldering-Benis-SMD-Solder-Benis-Adjustable-Thermostat-Mini-Pocket-Benis-Rework-Repair/32899329616.html

>>1514311

you're that nigger that everyone likes in spite of being a total nigger

you are the best troll i've seen since my usenet days

>>1514309
just get 10 10$ soldering irons and call it a day

>>1514315
i like him because he posts projects, even if they're dumb. it takes balls to post something you made on 4chan, unless it's a wojak or a rainbow dash rifle decal.

>>1514315
Check out these lights tho. Not bad for $15, they claim around 1000 lumens but like the 1 Amp thing, it doesn’t distinguish whether they are talking about each light or the pair. They came with some mounting brackets so you can tilt and swivel them and I would’ve liked to mount it on some metal frame rack but Home Depot didn’t have what I was looking for so I may just bolt them to a chunk of 2x6 and mount it all on there for the utilitarian retard look.

>>1514318
>i like him because he posts projects,

newport posts projects? are we talking about the same guy

hooking up lights to batteries is babby-tier shit. there's an LED lighting general. go play there or in traffic

>>1514321
is that not bepis posting as anon? i thought bepis was the one doing dumb shit with batteries.

>>1514319

>>1514323
>>1514324

this thread

>>1514323
I post a lot of dumb shit

Serious (dumb) question though:

If I wire it like this, the switch is on(PS)-off-on(BAT). So if I have the power supply plugged into 120V and I’m running the lights off that, the - of the power supply and battery touching eachother at the light won’t cause any issues, will it?

>>1514322
whats a good project then

>>1514326
>If I wire it like this, the switch is on(PS)-off-on(BAT). So if I have the power supply plugged into 120V and I’m running the lights off that, the - of the power supply and battery touching eachother at the light won’t cause any issues, will it?

/diy/ poetry

>>1513638
Tried the hartley oscilator, I give up on LC radio stuff, I`ll be a pleb and buy a quartz crystal and be done with it, or just use micro controllers. The only oscilators I`ve ever maneged to get working are the phase shift ones and wien bridges.

>>1514329
>mutefatherdisciplinesmutedaughter.png

Remember, I am retarded. I can’t even remove lug nuts properly. It will be fine tho, right? I think I read too many “dummies guides” written by shitty sources on the internet and it left me confused in some ways.

>>1514327
not him but if you want ideas my current projects are a radio controlled light dimmer and a precision multiplier (for a power supply or electronic load). the values on the latter are bullshit, correct values are still in a spreadsheet.

>>1514225
>didn't forged to put the kapton tape
mfw I read that as klingon tape...

>>1514329
it's only gay if the wires touch

>>1514336
may I recommend the Si5351? apparently it can even be made to produce quadrature outputs

>>1514339
>x-rated cap
BLUE BOARD

>>1514336
Colpitts and Hartley oscillators are apparently a little touchy wrt gain. this weekend when I'm fucking around, I might try a JFET-based Clapp, just in case chink-tier BJTs are the problem

>>1514329
>the - of the power supply and battery touching eachother at the light won’t cause any issues, will it?
it's fine

>>1514342
I wanted some sine waves to fuck around with a radio. all I wanted to do was make a on/off radio controlled switch reee.
>>1514346
what else do people use to generate RF signals?

>>1514353
PLLs or SAWs

Or instead of the 18650s, what happens if I hook up the power supply to the little 12V AGM battery? I think the power supply puts out like 12.2V. If the battery is >12.2V, the power supply won’t charge it at all?

>>1514296
If I get that, can I use the hot air for reflow assembly and not buy a toaster?

>>1514383
>>1514296
Also, is this temp controlled?

>>1514383
hot air is a bit of a pain in the ass because you have to balance airflow (which pushes smd components around) and heat dissipation into free air (which will have you holding the hot air gun over the board for 5 minutes without results). it works once you get a feel for it though. i've used it to solder 0201s, granted my hot air station is more expensive.

>>1514353
there's the AD9850 which is kinda expensive and a bit power hungry, but makes nice sine waves up to (IIRC) 125MHz
what kind of frequencies were you looking to generate anyway? the higher you go, the touchier they get wrt strays
but yeah, PLLs or SAWs

>>1514329
I want to see the twinkie house panel

>>1514383
meh, not really whole boards, at least not without a bottom heater e.g. hot plate, but you can definitely remove/install single components with ease
>>1514385
yes, both pencil and heat

I'm removing a cb radio from a truck I bought, the positive and negative aka black/red wires and the jack end are in annoying spots under my dashboard, can I just cut the wires and somehow tie them together or will it be some sort of safety hazard?

>>1514389
Using a hot plate would only allow me to reflow components on one side of the board, with the other side needing to be done by hand, right? Or is there some workaround?

>>1514400
I've never tried a double-sided board with a hot plate. I just use it for preheating largish boards while sweeping hot air over components on the top side. combined effect is that of a shit-tier reflow oven

>>1514311
>Not sure how to charge the Li-Ions
We told you last week, you paid no attention.

>there anything I’m doing totally wrong?
Yes.

I enjoy your fuckery , keep us posted.

How can I make it so my bluetooth headphones don't turn off when I plug the aux into it?

>>1514559
technical support goes to >>>/g/

I plugged probes of the multimeter to a wall socket and got 240v. I turned the dial to amps and suddenly I heard a huge pop sound.
I switched off the socket and removed the probes. I set it to do (with probes touching) and the do value keeps on increasing.. Like 300 v then 500 v then 700 v etc. Is the multimeter toast? It was a cheap one.

>>1514580
Does your meter not make you move one of the probes to do a current measurement? If not, yeah, it's toast unless there's a fuse.

>>1514580
Typo on second part. Meant to say ^set it to dc voltage without probes touching^

>>1514590
The red one was attached to "v ohm mA"

>>1514580
>turned the dial to amps
y tho

>>1514594
I thought it would show the max amps the outlet can support

>>1514596
Hint: it's more than mA range

>>1514311
>is there anything I’m doing totally wrong?
Yes, not ending your life.

>>1514565
No it's designed to switch off, I'm wondering if I could, for example, get rid of whatever detects the jack (while keeping the jack itself functioning of course). Or would I be better off hardwiring it to the drivers, assuming it isn't already?

>>1514593

Yeah, it's probably fucked.

>It was a cheap one.

Definitely fucked.

>>1514565
To be honest that's more likely to be a problem fixable by taking it apart and fixing some dodgy soldering (i.e. the mechanical stress of inserting the headphone jack moves a cracked solder joint and cuts the power for a moment), but chances are that's not it and it's a problem only solvable by reflashing some different firmware onto it. If it is one of those switching headphone jacks, it probably isn't solvable. But feel free to trace out a circuit diagram and see for yourself.

>>1514580
>>1514593
Basically, you put 240VAC directly across the sensitive small-signal electronics and fried the fucker. You'll get erroneous readings forever, dump it and get a better one. If it was one of those cheapy meters it will only be able to measure DC current anyhow. Get a ~$15 (Uni-t?) amp clamp and never use leads for measuring large currents again.

So learn Ohm's law, a voltage source of 240V will put out as much current as the load is trying to take, and any simple load will have a constant resistance. Through I = V/R, you can see that more resistance means less current. An ideal voltmeter will have an infinite resistance as not to potentially have an effect on the voltage it's trying to measure, but in reality the cheap meters have 1MΩ input impedance. The better ones have 10MΩ. In the same vein, an ideal ammeter has a resistance of 0Ω, while in reality they have a very low value resistance (0.01Ω or so) and measure the voltage across it due to Ohm's law (V = I*R). 0.3A through 0.01Ω is 0.003V, which is measured and converted by the computery bits into 0.3A to be displayed on the LCD. Going back to the first equation, I = V/R, we now know both V = 240V and R = 0.01Ω for our ammeter/amps mode of the multimeter. So do the calculation and find that the current that tries to flow is 24000A. This is a very large amount, and in practice your 0.01Ω resistor will have heated up and increased its resistance long before the current got that high.

>>1514636
cont.
Probably enough to evaporate the resistor, which would explain the "pop" you heard. But before that happened, you put a voltage somewhere between 5V and 340V into the IC and fried some of its pathways, so it's not reading right.

For your information, some typical current values are:
Kettle - 13A, 3000W
Toaster - 9A, 2000W
Computer - 3A, 700W
Phone charger - 0.05A, 12W

And power P = V*I (or V^2/R). An ordinary small resistor is rated at a maximum of 1/4 of a watt, so with 5V across the minimum resistance you'd want would be 100Ω, 0.05A. With 240V across a small resistor, the minimum resistance you could use would be 230,400Ω, 1.04mA. You put 240V across a resistor with a value 23 million times smaller than that. But it is a learning experience, so I'm not faulting you. I did that a year or so ago and blew a fuse that cost more than your multimeter did. So to avoid such things happening in the future, I cut my positive lead in half and spliced an inline fuse holder in series with it with a 5A fuse in it (compared to my expensive 10A fuse) such that I blow the cheap 5A fuse before my 10A can go on me in the event I forget to switch the leads back to voltage mode. Though in the event that you put your leads across a voltage source in the V/mA unfused mode, I'm unsure if this trick will save you. Also clamp-meters kinda suck for DC measurements (if the meter even supports them).

What device is this?

>>1514638
>come on, replace that old 25-year-old meter, they said
>it'll be fun, they said
no, I like having mA on its own banana jack and all this is exactly why I am loath to upgrade a perfectly good working meter

>>1514643
https://www.reddit.com/r/pics/comments/4g678s/found_on_the_circuit_board_of_a_guitar_pedal/d2f1gpe/
can't you google?

anti parallel diode in the red box
What does it do??

>>1514648
two Schottky diodes in a single package (possibly BAT54S). here, they clamp the VGRID_SEN and GRID_V_ZERO nodes to between 0V and 3.3V

>>1514638
Thank you, that reply cleared many questions I had!

>>1514648
Thank, anon
so the purpose is not to damage ADC of mcu right?

>>1514651
>>1514671
fixed

>>1514671
that sounds reasonable, it's a common motif

>>1514454
This is true, you goys have linked me to AliExpress a bunch of times for battery protection stuff.

What about >>1514379 ?

I remember with those solar panels the current was actually flowing from the batteries to the panels when the voltage of the panel was lower than the battery. So will that power supply only charge the battery if the battery is <12v?

>>1514676
Go look it up in the archive fucklord, we don't care. Should be easy enough for you, you have a trip, right?

>>1514682
Wut trip?

And faggots like you are why people hate generals. It’s almost as bad as the circle jerk Discords.

>7.4V
>no charger
Why????!!???

>>1514692
The one you post with so that you can "find your posts" you obnoxious cunt.

Is recom DC-DC module can be use as voltage reference ???

>>1514710
you could, but they're usually pretty shitty accuracy and regulation compared to even a meh linear regulator.

Recommend me an MCU.
It needs to have SPI, I2C (in order to communicate with OLED display), and UART (in order to communicate with ebike motor controller).
1 ADC, internal oscillator, because fuck crystals. Also it should work on 3,3v, yet tolerate 5v on some pins.
AVR 8.

>>1514728
literally any of them no wonder you are having trouble.
if you want i2c for oled you want fast or slow? data rate? probably for a speedo or something? figure this out will determine your clock rate but most newer chips will go pretty fast on internal clock now.

>>1514728
ATTiny whatever.

>>1514728
literally every shitty pic

>brother asks me to get him a new phone charger since i'm "so good with electronics"
>gives me money for it
>buy him one
>he looks at it
>"OMG you retard my phone needs a 5V 1A adapter and you got me 5V 4A, this is useless it will burn my phone! i thought you understood this electronics stuff!"
>apologize to him for being stupid
>give him my stock phone charger brick which is 5V 1A
>keep the "useless" 5V 4A for my own phone
just another tuesday in NPC land

Is putting resistor value inside its symbol a bad idea? Given symbol is a rectangle. I know it's about what situation requires, but is there a generic opinion on this? Working in kicad.

ds18b20 a shit ... A SHIT!!
fucking datasheets promised .1 deg precision, does this look like a fucking .1deg?
tenths are fucking useless when the are made by a random number generator

>>1512030
Which software would you guys recommend for circuit simulation and analysis? Preferably free of course.

Out of the ones recommended on the OP I've only used multisim, and that was at the university, so I'm wondering if there are any better options out there.

I'm a third year EE student if it matters.
I'm thinking of trying ltspice but I thought I'd also ask for suggestions first.

>>1514801
unfuck your brain, tantrum boy
don't believe everything you think
±0.5°C Accuracy from -10°C to +85°C

>>1514379

Somebody pls?

>>1514804
LTSpice

>>1514818
So you take more readings and average them to get a better approximation?

>>1514825

wouldn't that graph be the range for devices, meaning a particular device will be have a single curve, and repeated readings won't fix that, but could reduce errors due to things like noise.

>>1514804
PLECS on scnlog

>>1514825
You can average as you like for cosmetic reasons, but that doesn't affect the accuracy which remains unknown until measured. Also this:
"The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively. The default resolution at power-up is 12-bit."

>>1514732
Yep, a speed'o. Dunno, 2 fps would be good enough.
I just didn't know which chips do exist, and using 328 seems like a waste.
>>1514735
>>1514736
Not all. Some don't have SPI or UART. Some have only 2k of memory, and Arduino shitcode won't fit there, and I don't feel like diving into AVR-C and inventing my own libraries.

>>1514823
Damn are those blue newports? Dope pic anon.

I am curious about that power supply though. Will it charge the battery at all or only if the battery is super flat? I may have to experiment when I get some free time.

>>1514907
just use assembly, it works in all of them.

>>1514928
>just use assembly,

people think this is autistic, but in reality, programming something like an AVR or PIC is quite often easier in assembly.

>>1514745
nice work

>>1514728
many STM32F103 IO pins are 5V tolerant, and you have a lot of flexibility as to pin routing
internal oscillator is available
also you should use the parametric selector at microchip.com, this is exactly what they're for

>>1514794
it won't cause your circuit to blow up, if that's what you mean

>>1514907
whatever's cheapest and good enough, mane. it's not as if you can take the unused bytes out and put them somewhere else

>>1514932
Fukken kek

>note to self
>do not hook up 12V power supply to battery

This little part on the power supply started growing red hot and smoking

>>1514932
And it ocuppies less space, gives you intuitive knowledge on how the uC is organized and how diferent uCs work, makes you care about things you don`t in C or tarduino and forces you to read the manual The only time I use arduino is for quick testing shit, when I`m making the real thing I just take the 328, code it properly and put a bootloader in it.

>>1514932
can second this. i genuinely enjoy writing pic asm. the longest pic code i've written is maybe 400 instructions though.

>>1514982
>do not hook up 12V power supply to battery
i dont understand why you thought this would work.

>>1514990
Gotta test it to find out.

I mean with the Li-Ions, I can take 5V from a USB and go straight to a Li-Ion and charge it with nothing in the middle. It doesn’t make the plug start smoking and glowing.

>>1514993
why not just google "how to charge a liion" and do it the right way? it's only working now because the usb is either current limiting or just shutting off like it's supposed to on gross overcurrents.

>>1514990
Upside... the power supply still works

So I’m not sure which direction to go. I could do only battery and wire in this little charging port so I can hook the tender up to it. Or do only the power supply since it seems to have the balls to power both lights. Or do both of them with the 3-way switch and hope nothing starts smoking and glowing again.

>>1514995
Yeah I believe the USB port is current limiting, but the power supply also says 3A. And the thing on the power supply was glowing when it wasn’t plugged in or powered. And when I charge the 18650s with the USB thing, I use a 0.5A USB plug and keep an eye on the batteries with the meter. The 12V power supply normally charges 7.2V battery packs, right?

I have an actual power supply sitting in an Amazon box in my guest bedroom. 2 more weeks and I can get that thing smoking instead.

i bought this for my grandmother but it's way too fast for her. It has a TBW and as soon as you touch the throttle it takes right the fuck off.

How do i go about reducing the initial torque of the motor to be more amicable for a 101 year old bag of failing organs?

>>1515011
Add a shit ton of LEDs all over the thing to draw power away from the motor

>>1515011
i dont believe your grandma could sit on that seat. but why would you lie?

>>1515012
>>1515013
these are helpful posts and i appreciate the time you took to offer your input.

>>1515019
if you get shitpost replies it's because we don't know the answer. realistically we'd need to know how the throttle feeds into the motor control system. i think an RC circuit would work, for all the good that does you, but even if that's correct you'd need to know where to put it.

>>1515021
i was being serious you dick. you people are my only friends and i wanted to thank you for paying attention to me. what the fuck man? it's christmas

>>1515023
no problem pal. God bless you and your granny!

>>1515023
>what the fuck man? it's christmas
>>1515025
>God bless you and your granny!

>>1514967
>many STM32F103
I know how to work with 8-bit AVRs. Never worked with PICs or STMs.
>also you should use the parametric selector at microchip.com, this is exactly what they're for
Oh. I forgot about it. Fuck.
>>1514928
I'm too lazy to use normal AVR-C.
>>1515011
You have multiple options:
- Check your display. It might have settings for 'gears'. In low gears starting torque is low.
- You can file a shunt, or replace it. It will reduce power, and current, but it will accelerate smoothly.
- You can put a capacitor between throttle output and ground. It will make it accelerate smoother, but it will continue accelerating for some time, if throttle is released.
- If your scooter-thingy uses UART for controlling - you can modify firmware of display (yep). Make throttle response not linear, but exponencial.
- You can replace controller with programmable one, which will allow you to make it accelerate smoothly
- You can make a curve-corrector for throttle. Use some sort of Arduino (or bare MCU that runs at high speed, since you don't want any lags) and digital potentiometer or other sort of DAC.

Or just warn your granny that this thing is mad, and let her get used. With practice I can run it very smoothly, but I'm not sure if old people would be able to control tiny throttle with such precision, since they have shaky hands...

>>1515038
>>1515011
Anyway, do you want to sacrifice power and speed, or you want it just to accelerate smoothly?

>>1515044
i won't it to go slower than her walking. i'm 220 and i can get it up to 20 mph.

>>1515023
I think this is what I’ll do. Seems to work. And then I can add that little charging cable so I can plug the battery charger into whatever box I create to hold this stuff.

>>1512030
GAY

>>1515050
>>1515049
based. what are we drinking tonight?

>>1515044
got a rough explanation that i can google from on filing a shunt?

>>1515048
Okay.
>i won't it to go slower than her walking.
I don't think it is a good idea, since two-wheeled transport is unstable on low speeds.
20 mph (30 km/h?) isn't good either.
But yeah, you can safely remove some material from shunt (if it is not an SMD resistor), if you can sacrifice speed and power. If you had removed too much - take plumbing flux and solder it. Then remove flux with alcohol.
Just keep in mind, that at lower currents it won't be able to climb hills easily.
>>1515053
On picture you can see shiny wire with blob of solder on it. You will do just the opposite, you will remove some material from it.
It will make ECU think, that current is higher, than it really is. It won't affect efficiency at all. Actually, you might get more kilometers from same charge.

>>1514988
>>1514990
absolutely nothing wrong with c on a microcontroller
asm is like smoking, infinitely cooler and way more badass but you do it too much you will get cancer and die.
I used to prefer asm for everything but at some point you have to accept you are making things difficult on purpose. maybe one project in the last 5 years i had a phase sensitive lock in where i was counting cycles but other than that its just a time waster trying to do anything complicated.

>>1515051
$1 Iced Coffee from the ol’ Cumby’s. Black.

>>1515038
yeah, there is a bit of a learning curve to STM32
also note that signal level converters are cheap, available and pretty easy
anyway, hope you find what you want on the parametric guide

>>1515053
resistance is proportional to length and inversely proportional to conductor cross-section
voltage is equal to resistance times current
motor controllers typically use the voltage across a shunt to determine the amount of current flowing
assuming the current sensor is just a piece of metal wire, you can make the current-sensing shunt narrower to increase the controller's perception of motor current and thereby cause it to deliver less current to the motor
... assuming it's not the throttle pot itself that's touchy and needs to be cleaned

>>1515058
what's the smallest micro you've used?

>>1515066
>yeah, there is a bit of a learning curve to STM32
I actually wanted to order STM development board from china (something like Arduino Nano), but it was bluepilled. Literally.

Anyone has a rigold ds1102? are the ground clamps of your probes the same? I mean, if I set the reference in one probe, the other probe uses that reference too.

>>1515083
I think almost all scopes have a common ground that's also commoned with the earth lug of their plug, which is a reason why you might sometimes have to insulate the ground lug with a bit of kapton tape if you want to measure something relative to a different ground.

>>1515058
m8, assembly is literally retard tier, that is what makes it hard for some people, it`s just too damn simple. Also in a 328p or some other tarduino thing the chances of running out of any memory are very small (unless you are stupid and make a datalogger with the in-chip memory), so you only need to use assembly to acess normal functions of the chip, like proper interrupts, pwm and finer controls of acd and adc. If you try to use C for doing complex things in a cheap tiny uC you are done goofed.
>>1515085
Oh, I just got scared when ,measuring some H-bridges. Things got sparky.

>>1515090
The negative pin of a bridge rectifier will give you a voltage reference that varies between 0V and -340/170V, so if you're using one you'll probably need to leave your scope floating. The things should probably just have a 1MΩ resistor to the ground lug, and a relay that switches open if there's any current through the resistor.

>>1515093
The plot twist is that third worlders don`t care about anything so my medium-upper class building with 15 stories has no ground wire. I was with the ground on a -+36v rail and set the other probe reference to somewhere else after the diodes, the piece of wire I was using to reach hard places got spot welded to a component leg kek. Thanks man.

>>1515071
>letting branded /pol/itics get in the way of good cheap generic technology
wew
in fact, bluepills are excellent boards, with good processors, without a bunch of ridiculous crap in the way. their libraries are almost undocumented afaict, but their CubeMX configurator almost makes up for it

>>1515096
a subtraction function would be just what you need right now

>>1515128
>wew
It was a joke, obviously.
I actually still want to order it, but I don't want to go to post office just for one PCB, and for some unknown reason there are no sellers, which sell stuff I need and blue pill.

>>1515137
>there are no sellers
https://www.aliexpress.com/item/micro/32525208361.html
https://www.aliexpress.com/item/mezzo/32802852766.html
https://www.aliexpress.com/item/macro/32864003267.html

Hey /ohm/
I've been using logism for some time and have been trying to get good at designing logic circuits.
While logism is pretty solid for simulating it is pretty barebones and simple. Perfect for what I want however I keep running into one issue.
I want to control multiple segment displays.
I have a control circuit to display 1-9 but Im having problems designing a method to simply load a number greater than 9 into the segment display.
For example, in my counting circuit I've simply made a cascade into the counter which works for this specific task however let's say I add two numbers and they equal 12. Then I'm stuck not knowing how to display that.
I know google will tell me to connect them all to the same segment display and use a transistor to enable which ones individually. But at least for me that hasnt worked.
pic related is my cascading counter I mentioned

>>1515161
There were no seller, who sold shit I needed (SMPS IC, fuses, used BJTs (new are garbage usually), SMD resistor kit...) and bluepill.

>>1515176
that's part of the """fun""" of ordering chinkshit components: trying to combine your shopping list into as few orders/shipments as possible. I usually expect to need at least two for any sizable shop. I had much the same trouble trying to buy a balanced modulator (SA602/612) recently. almost nobody has 'em. still not sure whether they're new old stock or used

>>1515183
For my SA602s I got the SMT ones because I didn't want to pay $6 for 2 ICs, though working them onto my THT PCBs might be a little tough.

>>1515186
same here, tho the bulk of my work and component stock is SMT anyway
tip: those SOIC-8 adapter boards with some machine pin headers installed are perfect substitutes for DIPs and easy enough to put together. I plug the pin headers into a solderless breadboard at the appropriate spacing, drop the board with soldered SOIC on top, solder pins, and away we go. not sure how well the usual sort would play at the higher end of the SA6x2's frequency range but could be worth a try

>>1515049
I shoved my similar setup in a harbor freight ammo box.

>>1515202
I think I'll be fine trying SMT stuff, since the RF board or two that I want to use it on will be in that style anyway, though mostly with THT parts atop the pads. Main uses will be an RF condenser microphone and an up-converter for my SDR, but also just messing around with it at audio frequencies should be fun.

What does, for example, kV/V stand for? I can't get a straight answer anywhere. I need to know how to get that value from gain specs, like 1 mhz, which are the only gain labels for the lm358n. No V/V value and no conversion on google. Maybe I am missing something?

>>1515216
that's the kilo prefix
also Pic related may help

>>1515216
Probably gain: what factor the output is different from the input. Adding the prefix there prevents them from adding a bunch of zeroes in the datasheet. kV/V is identical to V/mV, and 100,000 V/V is a pretty large gain. >>1515219 is referring to an operational amplifier, for which having a very high gain is an important feature, and chances are you saw kV/V in an op-amp datasheet also.

>>1515216
note that A(vd) applies on top of gain-bandwidth product. GBW is a frequency dependent limit. e.g. max gain for a 1kHz signal through a 1MHz GBW amp is 1000 (V/V). but max gain for a 20kHz signal is 50, no matter how your feedback resistors are configured. further, at frequencies much lower than that, A(vd) will start to eat some of your gain
on top of all that, Figure 7 is a (typical) absolute limit on output swing by frequency. it is clear that the LM358 is not a high-performance op amp

>>1515205
I think I’m just going to make it out of wood, use that 2x6 as a heavy base and some leftover MDF scraps for the top and sides. Pic related ends up being 12”L x 6”W and I think I’m going to leave the front open so boxed on 3 sides and then run the cables out of the back. I was thinking about doing it in a metal frame, like that L-beam steel with the holes pre-drilled and I could bolt it all together and make lots of sparks with the grinder. But Home Depot didn’t really have anything that would work and I didn’t want to go to some specialty place to buy a single beam and waste their time.

I need to be up for work in 6hrs so I’m going inside to eat pizza and watch The Simpsons so I don’t think about this thing anymore.

>>1515229
> blog posting

So... I've been making Bluetooth speakers out of old stereo speakers and whatever i can get my hands on with bk8000L Bluetooth modules(i made one out of an old guitar cabinet... that sounded like shit, btw) and i never thought to add an aux Jack for plugging in other audio sources. Now I've decided to do that, and when i feed the audio signal into the aux in pads i get nothing. There is a pad labelled AUX_DET on the data sheet, but i have no fucking idea of what to connect it to. Anyone know where that should go? Picture related (it's from the data sheet) any help would be greatly appreciated since even Google searches turn up nothing useful...

>>1515273
you'll probably need to use a jack with a switch built in (these are usually normally-closed), similar to Pic related. try bringing the detect input to Vcc and see if it passes audio from the aux in

>>1515274
It looks like the left channel acts as a trigger in your schematic. I'll try connecting the left channel into the aux_det terminal. Will i need the filtering capacitors, though? Are they a necessity?

>>1515282
no, that's a normally-closed switch inside the jack. the general idea is to interrupt an internal audio path when something's plugged in. your jack may differ but the general idea, of using the normally-closed switches in the jack to hold the AUX_DET input low, still holds
the caps are there just for dc blocking. they block the dc from the switch
also, to be safe, they keep the aux inputs from going below ground
if your jack doesn't have a switch, you can't get the desired behavior with it
did you even test to see whether switching AUX_DET to Vcc lets the audio pass through?

>>1515285
I figured that a constant voltage wouldn't serve any switching purposes, wouldn't it just keep it on all the time if connected to vcc?

Any good textbooks on designing with LEDs?
Specifically I want to make a light using 5730L LEDs but I am more on the digital hardware side of things so I don't really know wheres a good point to get started.

>>1515299
Pic related shows more illustrative symbols for the jacks with switches
when unplugged (left), the switch contacts touch the jack contacts. when plugged (right), the jack contacts are pushed away from the switch contacts and therefore disconnected. usually this is used to pass an internal audio signal to the switch contacts, to be interrupted when an external signal is plugged in
if there is a resistor pulling down the jack contact and a larger resistor pulling up the respective switch contact, the switch contact voltage will be low when unplugged, and high when plugged
does it make sense now?

>>1515301
not much to it. add a resistor to limit current. on the web there are LED resistor wizards to get you started, given the LED voltage drop (should be specified), the supply voltage, and the number of LEDs, they will give you a resistor value and power rating required

>>1515311
Ill look into the LED resistor wizards, I want to build something that is controlled by a micro controller though, that is why I was asking for textbooks.

>scavange transformer
>nice, this will do for my psu
>two 16v coils and one 4 v
>want to make a 0-30v supply
>all coils in series
>36v
>lm324 and lm358 which were the opamps I`d be using are 32v max
welp

>>1515316
I guess I could change the main pass transistors to pnp so I`d be able to use a smaller tension and a 5-12V regulator for controls but I`d have to change everything..

>>1515314
Learn how diodes work. I don`t know what do you mean by ''led design'' but you`ll probably learn basic electronics anyway because of transistor switches.

>>1515301
If you're wanting to go into semi-budget (or extreme budget) then have a look at the circuits on lights that Big Clive reviews. Not sure if that's the sort of thing you're looking for but it should give you a fairly good idea of existing solutions in any case.

>>1515301
>a good point to get started
would be downloading the data sheet
https://www.leds.co.uk/application/files/8014/9519/3445/YJ-BC-5730L-G02.pdf
which seems to be newer than the one from yujiintl.com
If you do not have the binning code of your LEDs, assume a forward voltage of 3.3V at 150mA. The data sheet has the voltage bins (V30..V33) and a graph.

>>1515317
Follow OP's 'RULES' and post your circuit diagram like >>1512358 did. Blog posts we have enough.

>>1515317
Follow OP's 'RULES' and post your circuit diagram like >>1512359 did. Blog posts we have enough.

>>1515333
>>1515332
it`s a linear psu you mong, everyone here knows one

>>1515318
I mean that because the main trouble you`ll get with leds is powering them up reliably and safely.
>>1515335
>>1515333
and in case you don`t, pic related is the pnp one

>>1515317
yes, this is the recommended solution if you need to regulate from the low side. or, look up Sziklai pairs
the alternative is turning the entire circuit upside down, including but not limited to using opamps specified at the upper rail instead of the lower rail. 2/10 would not do without a very good reason

>>1515340
Thank you.
>two 16v coils and one 4 v all coils in series 36v
That's about 50VDC.
>BC548A
Vce max 30V
Reason for the low-B A version? BC546 has Vce=65V
>want to make a 0-30v supply
Me too (maybe 2x15V), that's why I ask.
What's your planned DC output current and what's the rated power of your transformer? Heat sink? Fan?

>>1512757
Are you sure you want to buy T12's? I bought as many different T12's as possible. I noticed the temperature was very stable, and they burned out quite fast. I bought T15s of the tips I use often. Also all the T12-1401 through 1406 are crap. Most only will melt one side of the iron.

>>1515371
>Reason for the low-B A version?
That doesn`t really matter for a psu, but no no reason at all, I don`t even know which one I have with me.
>That's about 50VDC.
>32+4v
>36v
>What's your planned DC output current and what's the rated power of your transformer?
5A which is the max a single TIP125 can take.
>Heat sink?
aluminum window rails or I`ll make one with sheet aluminum
>fan
If I find an old computer yes, I`ve already used the large pc fan I got on a plant grow box.
>rated power of transformer
I have no clue, I got it when a lab in my university was throwing old post-grad student projects away. Found some 10$ igbts, loads of copper for making coils, 2200uf good quality 65v caps.. I have some others here and a empty laminated core if I can be bothered spinning a new one.

>>1515311
Yes... Yes it does... Thank you very much for your wisdom, kind sir!! I'll be doing some tinkering later on today, if i can bring myself to working on my freezing garage for a little while.

>>1515379
>0-30V 5A TIP125 no clue
So no basic calculations.
Good luck then.

>>1515409
You asked for the power rating of the transformer, I got it from the trash, it has no markings. Learn to read faggot. I was planning to buy a 50W transformer, managed to find these and now I`m redoing the design based on the unknown one.

>>1515418
Original design was 0-20V 2A, now I have this of unknown rating. I don`t own a variac to caracterize this one but I know it can handle atleast 3A without overheating or saturating. The design isn`t complicated, I don`t know what do you mean with "basic calculations'' besides control loops which are functioning ok.

And if you are the guy asking about the bc548 Beta, it really doesn`t fucking matter, The pic has the low beta one because I just made a multisim model to validade some other things, I`ll probably end up using BD139 medium power ones

What changed from the design with a bought transformer and the one I got from the trash
>rectfied voltage is too high for the opamps and comparators I was planning on using, as I`ll not change those there will be a low voltage regulated rail
>with a regulated rail I`ll add a pic (probably two because of pins) to display stuff in 7-seg displays
>things to be displayed
>power in-out
>voltage setpoint and current voltage
>constant current mode trip point and actual current
also
>thermal shutoff

>>1515316
Just use a zener or a pile of diodes. Zeners aren't ideal to the model (they are specified at 10-20mA for the regulated level but drive up and down ~.5 V easily). You can find them rated at 250-500mW (25mA * 5V = 125mW). You'll want to watch your peak vs RMS. If you're just doing signal amplification you'll be fine. Actually using the op-amp as a driver it could be a problem.

>>1515318
Thanks for your help I work as a VLSI engineer so I know a lot about cmos and mosfets in general but only how they apply to silicon. What I mean by led design is mostly how to design supply. I’ll upload a schematic of the led array I want to power up later today.

>>1515562
Do you want to power it directly from the wall? Or you are planning on using already converted DC? Common LED lamps usually use something called capacitive power supply (or transformer-less power supply) so they can be made small. The downside is that it`s not isolated from mains, so only use it when fully encased and secured.

>>1515301
https://www.instructables.com/id/Power-LED-s---simplest-light-with-constant-current/

I like this circuit. the BJT doesn't matter, but you have to watch the mosfet. I scavenged one from something and it's more than 5V to get 1A out, so I can't use a 5V 2A supply for messing with leds. Ironically it saved me because I had a 34V supply and it was rated for 30V on the gate, but has a zener shorting the gate above that.

>>1515090
Retro City Rampage used C macros to write assembly. C is a fine language for high-level assembly.

>>1514794
European resistors are rectangular, and for SMD, values are usually given in "number-color" form. It would be unusual, but on a schematic you'd likely have capacitors as different symbols (for SMD they can be confusable with resistors)

>>1515562
>>1515571
B I G
C
L
I
V
E

Seriously, he covers like all the modern implementations of LEDs. One light-bulb even had 69 LEDs with a single resistor, for 230V power. Where he lived the voltage drifted up to 250 at the time of the video I think, so the bulb almost cooked itself.

https://www.youtube.com/watch?v=J825h--mC4k

>>1515347
I was going to flip my diy switching supply upside down to use NMOS instead of PMOS transistors, but decided it was easier to just have a little boost converter whatever on the +ve rail to get that little bit of extra oomf to turn the thing on. Bullet dodged I'd say.

i havent found a way to make an xor with bjt's so i made one
it werks but where's the catch?
if it's fine why didnt i find it under "bjt xor gate"

>>1515739
Typically an XOR is made by a combination of NANDs or NORs (both take 2 NOTs and 3 2-input gates, naturally the NOTs can be made of 2-input gates or of a single transistor), which themselves are somewhat easy to make with BJTs.

>>1515748
yeah but that takes more resistors and more transistors
it's also not symmetrical at all
nor gates also conect their inputs as far as i'm aware
what are the advantages of it vs my design

>>1515768
I think your design has suboptimal output impedance?

>>1515748
at the transistor level, it is usually implemented as A(~B) + B(~A)
lern2optimize

>>1515768
there are none
your design is clever and quite minimal, actually. downsides to yours:
>the output will be one diode drop below the highest 1 input. you will almost always want to put a buffer on that output
>the high power dissipation inherent in RTL
consider the X(N)OR gate Pic related (but in hardware please use larger resistors, say, 10k at least). it uses the input transistors as transmission gates, voltage comparators, and inverters. at * current will flow toward ground iff A XOR B. the buffered output is high iff A XNOR B, which you can buffer/invert again for a true XOR buffered output

>>1515798
>>1515810
turns out it doesnt work right
i have it hooked up to 3.5v and a led on the output and conmect a and b to 3.5v
it works as an xor should but there needs to be approx 0ohm resistance on a or b for it to work, even 5 and i get nothing
the voltage on a and b is -2v which seems strange
what is going on, did i wire something wrong?

>>1515829
you need to add 1k (or so) resistors on each transistor's base so that the one closest to ground doesn't hog all the input current

>>1515844
if i do, nothing happens
even 5 ohm on base make it not work
i'll work on it tomorrow, its 1am

>>1515829
Try it with other loads or increase the voltage. I searched for bjt logic gates nor on google and got pic related. If you want to do ttl logic there are probably thousands of old books on your closest library about it

>>1515857
comparing your circuit with what I`ve found it seems that you lack two pass transistors (which have a logic of their own as you can see) that interface the main logic switching with whatever you are switching. Also it`s a good excercise to calculate the bias point of your logic gates see how much current they can take before going weird

So what exactly do I have here? I have searched all the numbers multiple ways but can't get the data sheets.

Could these be useful? I got them years ago during a business liquidation for free but am only just getting into electronics.

>>1515867
looks like resistor networks. the one in the lower right is 220 ohms/330 ohms, probably 18 pairs of them as in Pic related (passive SCSI terminator?) and the one in the upper center is probably the same
you can use an ohmmeter to measure them and map them out if you like, but you'd be hard pressed to find a use for that configuration, especially if you're only just getting into electronics

>>1515867
Resistor ladders/arrays, if you can't find the datasheet (or otherwise figure out the tolerances/resistances from the markings) they're mostly useless. If you do find the tolerances and they are low-tolerance, you may be able to use them for ADC/DAC work, or whatever the hell resistor arrays are typically used for.

Anyone here done diy solder mask after etching a PCB? Going to get into PCB making via Big Clive's method of using screen-printing transparency and iron-on photoresist.

>>1515917
Ok I watched this video:
https://www.youtube.com/watch?v=wvU2yyfH-XE
And thought that if some adafruit basedmale can get passable results with an already-cropped PCB then so can I. So since I'll already be using transparency to expose the photoresist, I bought a $1.50 tube of solder mask to go with it. If it goes well I'll post results. In like 2 months when everything arrives.

>>1515933
>adafruit basedmale
what did he mean by this

>>1515980
oh, hiro has an word filter for s-o-y into based

I've been watching a lot of diy projects for Arduino, but I don't know anything about programming. In recommendations for learning?

>>1516014
Python is easy as fuck, copy a "hello world" code, copy a function, copy a few loops, copy some boolean and "if" statements, and you basically know the language. Stackexchange should have all the answers ready to copy. Import a few libraries when you need them, it's fun.

Later you'll realise that the common arduino MCUs (AT whatever) don't work with python and you have to learn whatever kind of C that is. Then just make your arduino code 20 lines of copy-pasted code from a handful of websites and let the imported libraries do all the heavy lifting. If you know how to make a delay and call a function, you can code arduino. And probably interrupts too, whatever the fuck those are.

t. can't code

I just ordered some /g/csg-tier IEMs and I've heard some (probably greatly exaggerated) rumours of the drivers taking some time to burn in and develop their sound after buying them. So I figure I can attach an electret mic to an MCU's ADC and whip up some sort of housing to hold the IEMs a fixed distance from the microphone, then do a "bode analysis". There will be some nonlinear frequency response in the circuitry, but the purpose is simply to make a comparison, not an absolute measurement.

So my question is, is a square wave directly from a digital pin going to work well enough without issues, or will I need a DAC?

>>1515933
and they're doing some pretty big boards with it, too. not bad. I think I'll put some of that on my shopping list

>>1516080
the current draw of the load would probably do bad things to the micro if the back EMF didn't get it first
consider using a simple LM386 power amp circuit. connect your square wave output to DIG_OUT. start with RV1 fully counterclockwise and adjust until you get a decently loud volume when worn or until volume stops increasing (in the latter case, back off a bit). this will give you reasonably clean, reasonably flat, reasonably symmetrical output from 100Hz to 10kHz, and still provide useful data for comparison beyond either end of that range

>>1516080
>>1516095
*R1 should be 47k

I have fairy lights that have a detatchable RF wireless module and remote. With it you can set the brightness, modularity, and speed.

I want to be able to control the lights from my computer (like through console commands). How can I do this?

>>1516114
>how do I hack consumer electronics
this is an art that takes months or years to learn. RF reverse-engineering is a whole art to itself and 90% likely you don't have the tools for it
building your own controller to replace the existing controller and remote is probably easier than trying to reverse engineer that one. no doubt there are even step-by-step arduino projects to walk you through it

>>1516120
>>1516114
Not necessarily needed as long as you are willing to have an abomination of a project looks wise.

-take off the cover of remote
-get an Arduino nano (2$)
-connect a digital pin to every button on remote effectively replacing them w/ the Arduino
- make the Arduino take commands via USB (via com port) and virtually press the corresponding buttons
- you can now control the lights via your PC.
Bonus points if:
- make the remote run on the arduinos power so you don't need batteries (it's likely a single cell battery so around 1.5V)
- write a python / C / anything else Programm interfacing with the com port to make it more convenient and not need the Arduino IDE running.

You can now control it with your PC instead of having a much smaller self contained unit that does the same thing.

Only do this if you want it as a small project/like the building process/want to learn. If not it's a waste of time.

>>1516095
Oh yeah I'd need to high-pass it and almost certainly buffer it too. I'd personally just use an audio op-amp in a buffer configuration and fix the divider at ~1:20 or so. I probably will need DC-blocking capacitors on either side of the op-amp, which I'll have to select to be as linear as possible, so perhaps a corner frequency of 1Hz.

I just wrote a quick'n'dirty python code as a proof of concept and it works pretty well. It just sets the output frequency, collects 4 peak values and averages them, then assigns that average value to the frequency value in an array, steps up the frequency, and starts again. Except the "samples" are just the result of a transfer function I wrote.

I have no clue how I'd make a list/array/vector of data in C++ and add to it as I go, so worst-case I just do so to a string and split it, assuming that's easier. Holy fuck this language is more obtuse than babby's python.

>>1516122
>USB
Isn't it possible to use a serial and/or parallel port on a computer for this sort of thing and manually pull pins high and low like one would with a raspberry pi?

>>1516127
Probably, but why bother. Use a USB to power it and do the data transmission and save yourself a lot of time.

Directly interfacing with the hardware is a lot of additional work for almost no payoff (1 unused USB port that is)

>>1516123
if you're using lolduino it might be enough just to print your data as strings to the serial port as you collect it, especially since you don't have all that much RAM on board to store it

>>1516122
oh, yeah. there is that, if you don't care about the original remote

>>1516127
>serial and/or parallel port on a computer
time travel is real

>>1516122
yeah this sounds like a good start. Where do you get arduino nano for $2?

>>1516120
yeah figured that would be the case. that's more what I had in mind (that's why I emphasised detachable). But it's possble to buy/build my own controller?

>>1516138
>Where do you get arduino nano for $2?
from china

>>1516138
AliExpress if you don't mind waiting. It's not genuine but the hardware is open source.
eBay works just as well. Just look there.
I got a 5 pack for like 9$, none was faulty but you never know.

>>1516138
oh, if you just want to replace the little shrink-wrapped bit with your own work, it's pretty easy
the hardware end of it is just a logic-level n-MOSFET connected in line with the ground of the light strip (IRL520N is good) with the + passed through. apply logic 1 to the gate of MOSFET, lights turn on. apply 0, lights turn off
software-wise, you might have better luck searching arduino forums for an acceptable controller program. this one might get you started, just connect the MOSFET gate where they connect LEDs to the resistors
http://diwo.bq.com/en/control-an-rbg-led-from-your-computers-serial-port/

Is Voltage sensing circuit like this should be ground to earth???

Anyone got recommendations for a gate driver for use with stepper motors? I'd like current sensing and microstepping, ideally.

anyone know a good current sensing circuit with cheapo part down to the miliamp range?

>>1516232
you can tie gnd to earth or to the output of a bridge rectifier. what matters is that the inputs on u12a don't exceed their voltage rating (operational, not absolute).

>>1516397
depends on your application (ac/dc) and the full scale range you need.

>>1516424
high side current monitoring, input 0-25v DC, 5v supply. max current 5A

I wanna get into electronics, would UNI-T UT210E True RMS be an acceptable multimeter? Seems to have all the functions I could need. Are the capacitance/resistance ranges acceptable?

>>1516440
m8, just get any multimeter. This isn`t /p/, buyfaggotry won`t get you anywhere. Maybe you`ll progress to the point of making your own bench voltimeters with ramp adc :)

>>1516447
this, necessity is the mother of invention
the more crutches you use, the less you learn

>>1516447
for the record I started with pic related last year. I`m not saying "hurr you got to be manly and make your own galvanometer with paper clips and use pencil leads as electrodes hurr durr", it`s just one of the few fields where you HAVE to understand what you are doing, otherwise it won`t work at all. So my advice is to buy a book instead of a multimeter or both, and if you have money to spare buy a nice one yeah, it`ll make your life easier. In my short 2 year experience with this I`ve learned there are a couple things you cannot cheap out
>osciloscope (don`t buy random tiny usb chinese stuff or thos DSO-somethings)
>soldering iron
>screwdrivers, pliers, crimpers and the like
>things to store components (kek)

>>1516487
what about power supplies

>>1516490
make one? It`s the ideal first big project. I`m making mine right now

>>1512030
Anyone know what this plug type is? How can I /diy/ it to work with modern USB3 or microphone jack for computer?
It’s for an old mic I found at an old-shot-store (next pic related)

>>1516507
This the mic

>>1516507
>>1516511
Most of the D104 microphones I've worked on have a connector with a 'key' slot. I've not seen one with a D style.
That mic is very popular with HAM operators (and CB'ers) so ask over in that thread.
Protip, don't mention CB over there.

Gonna build a UV lightbox, anyone got tips or tricks for me? I'll probably go for a capacitive dropper circuit, with a ~470nF cap and 30-50 5mm UV LEDs running at 20mA. From what I see of capacitive droppers, a resistor is also included in series with the circuit, both one before and one after the bridge rectifier, should I include these?

I don't know if this is the right place to ask, but what exactly happens when I shift the frequency range of my rtl-sdr? Is it like changing a litte tuner inside it or is it just some software wizardry?

>>1516779
do include the resistors, one in series with bridge to limit inrush current, one across the smoothing cap (assuming you're using one) to discharge it.

If there's any chance you could touch the wiring/LEDs while it's on I'd recommend using an isolated driver module / DC supply instead, they're not that expensive

>>1516870
It is a tuner, you're setting the local oscillator frequency gets subtracted from the RF frequency you're interested in so that it's low enough to be sampled by the ADCs.

>>1516490
0-15V 1A PSU for $30 will be all you need to start.

>>1516871
I was thinking that one in series with the LEDs after the rectifier is something I see often, I'd be putting resistors in parallel with the capacitors anyhow. Perhaps the extra resistor in series would be to fine-tune the current being limited by the capacitor? I suppose inrush limiting does make some sense, but however I simulate my dropper (I've no idea how I'd calculate the correct capacitor size without a sim) I can never seem to get a current spike when I turn it on, and even if there was one it would be at a low voltage thanks to the 100µF cap absorbing all that energy. Either way I've got an excess of resistors so I'll dump one in to limit inrush anyway.

I'll consider a different sort of power supply, but since it will have to be a current-limited med/high voltage thing, I'll probably have to make it myself. In that case I guess it will be good practice for my power supply (what I'm getting into PCB making for) but for something I'll barely use I think I'd rather just house it in an MDF box and treat it with appropriate respect.

Thanks for the tips!

>>1516904
there are a number of reliable current regulation solutions to make your life easy here, from two-terminal preset current regulators (Diodes Inc. AL5890) to off-line current regulators like Pic related

>>1516923
I was thinking more out of what I have lying around, but wow is that HV9922 switching circuit nice looking. As simple as 3-terminal linear regulator. If there are potentiometer adjustable versions (both CC and CV) I'd quite like to buy a dozen.

Could someone recommend a book on control theory?

>>1516957
Actually now that I think about it I could try and use a JFET as a "constant current diode" instead of another current limiting resistor, which would have the added effect of smoothing the voltage out, which if I only use to drop ~6V or so will be quite effective without heating up much, which also allows me greater leeway with choosing a filtration cap. And since I have some JFETs lying about I might as well give it a shot, though they are RF transistors.

Also anyone have any hot air station recs? Chinkshit or otherwise, but not hugely expensive.

>>1516957
there are a few off-line buck voltage regs around, Pic related is almost as simple as any other buck and is available from some ali sellers
if you want an adjustable current regulator, the AL9902 is interesting and easy to use, works up to 1A, although the reference voltage isn't adjustable so you have to adjust the shunt instead. also, not available on ali as far as I can tell, and Digi-Key is closing them out

>>1516997
>hot air station
Aoyue 4 lyfe

i grow stronger

>>1517155
now you can carry

>>1517269
i dunno if i'm a retard but sometimes i get voltage out when there shouldnt be any on the xor
should i be testing for current instead?

I'm trying to copy this veroboard diagram but I'm kinda stuck at the caps.
I'm guessing the round purple-ish caps are electrolytic, the one labeled 51p is ceramic and the ones shaped like brown elipses are polyester, right?
I usually buy my electronics on tayda are they a good place to order a bunch of ceramic and polyester caps? All I have are electrolytic

>>1517288
Also Tayda doesn't stock 51pf are they hard to source?

instrumentation-amplifier-ground-loop-isolator
from this article
How to earth the sensor circuit???

>>1517312
http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/measurement-techniques/instrumentation-amplifier-ground-loop-isolator