/diy/ - Do It Yourself

>>1452945
this thread's digits brought to you in part by the LTC2945 wide-range I2C power monitor

How do I drive a 6V 10W halogen lamp? I know there is a considerable inrush current that needs to be dealt with, and I want to achieve this without dedicated IC's, I have all common circuit components available. Doesn't seem to be a great deal of info on google without resorting to "use this IC with a mosfet".

>>1452999
you don't need anything more than the MOSFET and the gate signal, if you size it correctly
10W ~= 1.6A at 6V, so the MOSFET Ids(max) continuous should be > 1.6A
6V / 1.6A ~= 3.6 ohms continuous, so you'll want a low enough Rds(on) to maintain a proper steady state lamp voltage and current and not generate too much heat in the MOSFET
measure the cold resistance of the lamp and ensure 6V / (Rlamp(cold) + Rds(on)) is less than the Ids pulse rating of the MOSFET for the turn-on time of the lamp (in fact, the increase in resistance over the turn-on time allows some margin)
does that help?

>>1452999
I use a switch. You can calculate the maximum initial current by measuring the resistance of the bulb at room temperature, but you do not need to supply that current to light it up. If you limit the current you have a soft start which increases the lifetime of the bulb.

>>1453025
>>1453029

I see so I just need to setup a constant current with something like an LM317 (1.6A is slightly above max recommended), and have a mosfet after it in series to switch?

>>1453040
nothing so extravagant as that, an RC on the gate will do nicely. the MOSFET's current passing ability depends on gate voltage

>>1453040
You never mentioned your power source. My reading lamp is 12V 10W and the halogen bulb is powered by its small 230V to 12V transformer which also does the current limiting. The light bulb shows 1.2Ω at 25°C (77°F) and it takes about half a second to light up because the 12V/1.2Ω=10A never materialize thanks to the internal resistance of the transformer. A halogen lamp needs no DC power supply.

>>1453102
Sorry I completely forgot this point. I was initially aiming to run it off a 6V DC source, using a voltage divider on a normal 3A 12V dc power supply. That way I could run two at once to improve efficiency. However as my project is supposed to be a bit more portable I have decided to use a USB power bank as the power source. It has quickcharge 3.0 I believe so I'll need to check the specs for how it responds to powering a load like this instead of recharging a battery.

I tried the LM317 as a constant current regulator from the 5V USB power supply but it is disappointing too much current as heat. The whole idea of this was to use it as a light source for a mini-spectrometer hence the portability and not using a simple LED instead (halogen lamps have a nice continuous spectra).

I'll try >>1453081 tomorrow. As people can probably already tell, I am a brainlet when it comes to electronics.

>>1453225
lol

>>1452999
The simplest solution for inrush current limiting is a NTC thermistor. This is likely to be cheaper than a MOSFET. However, it will probably drop about 0.5V.

>start college Fall 2017
>want to earn BSEE
>soonest I can complete prerequisites and transfer from CC to Uni is Spring 2020
>which would require I take
>>Calc III
>>Diff Eq
>>Engineering Physics II
>>Chemistry II
>all in the same semester
and that's just to start my major
I don't even know how many years it's going to take me to complete it since I can't read the fucking flowchart
I'm going to be like 24/25 by the time I get this degree, I can see my youth eroding before my eyes

>>1453390
may be able to skip some initial courses if you did similar stuff in HS, check the requirements I guess.

>>1453390
Dude, i started late as hell and will graduate at 30 most likely. I know others my age doing the same. Try not to worry about age and do your best, thats my plan.

I could always take extra classes each quarter and maybe ill save some time but i cant afford it.

I'll be taking calc 4 along side engineering physics and an electric circuits class in fall. Im surprised you have to take gen chem 2 for your degree.

>>1453461
>Im surprised you have to take gen chem 2 for your degree.
I said the exact same thing. The only application I could think of for chemistry in EE is PCB/Wafer etching and some rare edge cases involving interactions between certain materials

I'm not even sure what the course designation is, I just wrote Chem II for simplicity's sake, and Int. Chem for Introductory Chemistry. See the lower left of the flowchart, I need to take Principles of Chemistry and its prerequisite, which seems to be fucking me up a lot.

>>1453461
>Im surprised you have to take gen chem 2 for your degree.
I said the exact same thing. The only application I could think of for chemistry in EE is PCB/Wafer etching and some rare edge cases involving interactions between certain materials

I'm not even sure what the course designation is, I just wrote Chem II for simplicity's sake, and Int. Chem for Introductory Chemistry. See the lower left of the flowchart, I need to take Principles of Chemistry and its prerequisite, which seems to be fucking me up a lot.

>>1453390
Id do diff eq in 2020. Youd want your calculus all under your belt before you get into it. Or ask the math dean or one of your professors later.

>>1453464
electrochemistry

Is there a battery the size and form factor of a D, but higher voltage, like a 3v instad of 1.2-1.5v?

>>1453494
No. They intentionally don't make batteries with different voltages use the same form factor.

>>1453494
https://en.wikipedia.org/wiki/List_of_battery_sizes#Cylindrical_lithium-ion_rechargeable_battery

>>1453390
They put you in a general Engineering program. For my CC:

>CalcPhysics 1, 2, 3
>Chem 1 (I got 102 substituted since I took AP in high school and was comfortable with the basics
>Calc 1, 2, 3, DifEq
>Statics, Dynamics
>Circuits&Schematics
If you pester them you can probably get a few courses replaced. I suggest AS MANY AS POSSIBLE BEFORE TRANSFERRING. Even if you run a part-time semester at the end, the 5-10k+ you'll save will be worth it. Part time college would also give you some time to explore your new knowledge, including finding a co-op or internship if you can.

I've been looking for EE work, and although I much favor embedded systems (I'd like design, I do programming), many EE jobs are power and drafting circuits.

>>1452999
An inductor with a flyback diode. You can use a plain switch. For a lamp it'll be fine with current going the other way during shut-off.

>>1453503
Diode is across the inductor. Forgot that's how flybacks work. There's no reverse current

>>1453494
D-size primary lithium batteries exist.

>>1453500
they sure do, Li-ion 3.7v 14500 is same size as regular AA for example.

>>1453494
Li ion 32600 size is close to D.

>>1453503
Calculate the required L of the inductor for a start-up time of 1 second. Make reasonable assumptions to simplify your calculation. Document and justify your assumptions.

>>1453521
enough inductor for a 1 second start would be yuuuuuge.

>>1453531
L = R*t
Yes.

>>1452999
use an RC circuit to slowly turn on a mosfet. the mosfet's vgs-id curve won't line up with the rc charge to give a consistent brightness ramp or anything, but it'll soft start at least. the linear range of a mosfet might be ~1v or less around the threshold so the values (ijncluding the zener) might need tweaking.

Does anybody sell homemade electronics on tindie or other sites? How's it going? How does the shipping works out in the final price?

I want to sell tiny useful PCBs at low prices, but I'm not sure if the shipping would make them too expensive. I live in Europe.

so as a prospective BSEE major (>>1453390) still doing their gen ed (and thus can't do internships, as far as I know) who's only worked at a grocery store

what job can I *try* to get that'll look good on a resume? I'm not sure if working at a computer repair shop would work, but it's the only thing that's possibly part time that I can think of

>>1453583
once I get competent enough at designing circuits I want to sell home-made synthesizers and effects modules. Not sure about anything further than that like shipping though

>>1452945
Anyone know of an Android/iPhone alternative for KiCAD?

>>1453620
There is none. Design of schematics/PCBs on anything touch is retarded.

I bought a pair of battery heated socks. They run on 1.5v D batteries.
I assumed it would be one sock/one battery pouch, but it is a belt buckle pouch for both battteries wired as in pic.
(red = heating element, green = sock 1, purple = sock 2)
It has been awhile since I did any electric stuff, but pic diagram means they're wired in series to create 3v, right? So if I cut it in half, I actually have two 1.5v heated socks instead of 2 3v, and half my heating potential?

>>1453723
If everything is in series and both heating elements are the same, then the 3V is split equally between the elements.
Each element gets 1.5V, so 1 battery, 1 element would be the same.

>>1453390
get ready to suffer.

>>1453726
Does that diagram represent in series or in parrallel? I'm not entirely sure.

>>1453620
>being this retarded

>>1453783
>Does that diagram represent in series or in parrallel? I'm not entirely sure.

https://www.allaboutcircuits.com/textbook/direct-current/chpt-7/what-is-a-series-parallel-circuit/

>>1453733
so help me lord, I will fist fight god himself to get this degree if I have to

>>1453805
So it is indeed in series. So, if I swap out the 1.5v D for 3v 32600's, I would get double the heat output at risk of melting the element?

>>1453814

i suspect the element can take it. being next to skin, it's not being pushed very hard currently. your foot might not like it tho.

>>1453814

it's actually 4x the heat. power = voltage squared divided by resistance.

i suspect the element can take it tho. being next to skin, it's not being pushed very hard currently. your foot might not like it tho.

Got a quick question.

I have a pair of Ultrason HFI-780s that have a male 3.5mm aux cable coming from the cups. I cut it out, and installed a 3.5mm female aux jack that I got from the local electronics store for $3. Everything works, but my sound quality is bad now, mainly with deep noises (such as voices) and the bass. Did I just get a cheap jack? Or is this likely due to my shitty soldering?

>>1453876
Sounds like there might be a ground fault, i.e. all the power is just going from L to R. Check continuity and resistance a bunch. Use plenty of flux when soldering. Make sure the socket makes good contact with the jack.

>>1453876

the previous dude is probably right. either the ground connection is missing, or you shorted the L and R.
no matter how shitty a connector, it wont affect the sound quality, except to make scratching noises when you move it.

>>1453876

the previous dude is probably right. either the ground connection is missing, or you shorted the L and R.
no matter how shitty a connector, it wont affect the sound quality, except to make scratching noises when you move it.
another possibility is the store sold you a mono jack. (even if it has 3 pins, it could be mono, the third pin being a switch)

>>1454033
>even if it has 3 pins, it could be mono
Had this once, though to be fair we simply couldn't tell since it looked identical to the stereo socket. In this case the extra pin was just an artefact of the same housing being used for the manufacture of both the mono and stereo jacks.

>>1453225
From 0:02 I already knew how it was gonna end, and idk what that circuit even is.

>>1453599
Work as a game tech at a Dave&Buster's

>>1454084
CW multiplier.

>>1454093
>CW multiplier.
THankk you for the proper name.
>Lv AC --> Hv DC

I want to make the voltage regulation in this buck boost converter more comfy so i want to remove the gay little CV trimpot and replace it with a chad potenciometer.
But the problem is the trimpot is 2Mohms and i only have 100K potenciometers.
Will it work with a 100k?

>>1454282

Any EE's in the thread? I'm doing my apprenticeship and i'm considering going back to school next year to do EE and keep working on my hours during the summer
Anyone do anything similar?

>>1454283
>2Meg potentiometer
That's quite high for feedback, you sure you're measuring it correctly?

Anyways, if it is adjustable resistor - see what values you are using. Because if it is indeed 2Meg range you'll end up with severely reduced voltage range stuck in either on the top range or bottom range.

>>1454312
You were right. It turns out there are 3 trimpots there but not all of them are same value as i thought, the VC one is 100k this is perfect

>>1454282
>this buck boost converter
is a boost-only converter

>>1454405
no it's buck boost, it can't go both up and down

>>1454432
>it can't go both up and down
correct, that's why

>>1454485
i meant it CAN go both up and down.
If i connect say 5V on the output i can go both down to 2V or up to say 15V

>>1454493
*input

>>1454493
Link to the product?

What is a current source and how does it differ from a voltage source
I just can't imagine a current source without a voltage source, since as far as I know you need a force (voltage) for something to flow (current)

>>1454614
they're both theoretical constructs. the ideal current source will supply a current at up to an infinite voltage, determined by the resistance of the load according to Ohm's Law. the ideal voltage source will supply a voltage at up to an infinite current, determined again by the resistance of the load per Ohm's Law
real voltage and current sources are real and therefore limited in how well they keep up with a load

>>1454614
a current source will provide whatever voltage is necessary to get its target current to flow.

I have a bunch of these LED strips and I have this 9V .8A charger that goes to God knows what. Could that power these? Should they be wired in series or parallel?

>>1454639
no
>charger
wherever you came from, go back

>>1454643
Something tells me you don't have a real answer and are just a butthurt faggot.

>>1453599
bumping this

>>1454659
why do you even want an internship? you won't do real work there.

>>1454639
>>1454656
the little black chip that says 2490 is a resistor. how many leds are there per resistor? it's necessary to know the supply voltage for the strip.

>>1454673
Same reason I want a $40000 piece of paper. It's a popularity contest and I gotta play the game if I want to win.

>>1454689
i made out pretty well without an internship, and i'm pretty sure most of my coworkers didn't have one either. just enjoy your free time while you still can.

>>1454676
They said 12V on the site, but I tested a 9V battery with them and it was able to light those up.

>>1454692
survivorship bias my guy
I gotta raise my odds as high as possible or else I won't feel comfortable with the probability of me getting a job

>>1454751
Each LED will be about 3V, count the number of LEDs and number of resistors. It's probably 1 resistor per 3 LEDs in series, and lots of those in parallel, so about 3V would be dropped by each resistor. In this case you can figure out the approximate of current by dividing 3V by the resistance of the resistors. By running the lot with a 9V power supply you're probably putting through less than 1/10th the intended amount of current. This isn't bad for it, just you'll likely not be getting the amount of brightness you're looking for.

anyone know any clever tricks to measure the crossover frequency of a passive (LC, 2nd order) crossover?

>>1454788
could see how it reacts with a square pulse

>>1454788

use a software sine-wave generator, plug in into input of filter, measure AC voltage out as you sweep the frequency.
no DMM with a low AC volts scale? use a software scope, tho that might require a second sound card, or a second computer.

>>1454790
>>1454810
i plugged it into a headphone jack and looked at the outputs on the scope. They're both flat across the audible range. Is it not going to function correctly without a load?

>>1454815

a load should not be necessary. remove scope and listen to output using headphones. that should point you in the direction of the trouble.

>>1454815

a load should not be necessary. remove scope and listen to output using headphones. that should point you in the direction of the trouble.

for example, if the scope-in and sound-out share the same ground, then the polarity of the scope connections matter. plug it in backwards and you're shorting the signal.

or the signal out is just too smol.

i have a thermistor attached to arduino mini which i want to use as ADC basically. I also have raspberry pi and i want the arduino to somehow communicate with raspberry so i can read the thermistor in python on the raspberry
what would be the easieast way to do this?

>>1454820
to make it more simple, the arduino measures a voltage on its digital pin and i need to send this number somehow to the raspberry

>>1454821
*analog pin

>>1454821

spi, i2c, rs-232, infrared, radio, etc

https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial

>>1454823
That seems all complicated as fuck. I literally need to transfer just one number. Surely that is something two wires and couple lines of code can do

>>1454639
Led strips are 12V in most cases so the will be dim.

>>1454639
9VAC is always a good idea with 12V strips, wonderful dim flicker. Should you want it brighter, add a bridge rectifier and maybe a storage cap.

>>1454855
>9VAC
that is a bad idea, AC will make the LED strip blink very fast and cause epilepsy seizures

>>1454862
>what is PWM
60Hz is fine, plenty of LED lights use rectifiers without filtration caps.

>>1454864
PWM is literally ON OFF ON OFF ON OFF
the worst kind of power to put into a light ever

>>1454864

Even shitty, non constant-current drivers do PWM in the kHz range, far above what's detectable by a human.

60/120Hz flicker is VERY noticeable. Even when you're not moving fast enough to see it directly, it still gives a feeling similar to being in a strobe light (mostly because that's exactly what's going on).

>>1454639
>series or parallel?
If AC then anti-parallel. Increases brightness and reduces flicker.
>>1454866
Of course, but you can fool yourself and pretend not to notice. You cannot deceive your nervous system though, especially not the peripheral vision.

>>1454846
>Surely that is something two wires and couple lines of code can do
and that's why you're asking such a novice-tier question here
anyway, a UART would be the easiest to understand and debug method. it's pretty easy on the lolduino side, you just need to configure the pi's kernel to enable a UART on the GPIOs https://sites.google.com/site/semilleroadt/raspberry-pi-tutorials/gpio
then you can send numbers, text, dirty pictures all damn day if you want. you can even hook your FTDI adapter up to a terminal program to replace either the pi or the lolduino for debugging purposes, should you want/need to

>>1454821
Just use a PWM signal

>>1454925
elaborate

>>1454949
Well I've read into it a little bit and it doesn't seem very reliable on the raspberry pi's side, so for good measure I'd still say go with the serial option.
PWM would mean an analogwrite of the sensor data on the arduino's side and something like http://abyz.me.uk/rpi/pigpio/code/read_PWM_py.zip on the raspberry's side to read the pulse width.

>>1454951
I am looking at the various digital methods and i just want to find the laziest one that has libraries for it in both python and arduino so i can make it work in like 5 lines of code

>>1454972
then UART is the one you want. literally just Serial.write() on the arduino side
pi python side is at https://electrosome.com/uart-raspberry-pi-python/

>>1452945
>replace one of these switches since the old one was sparking while on
>take my sweet time doing so because its a cheap pos
>like literally an hour
>try it
>it only goes on when the other switch is in a certain position
I want to kill myself

>>1452945
>Michael Jay Geier, How to Diagnose & Fix Everything Electronic
This has helped my ass many a times as a quick reference

>>1454865
Yes and no.

>>1454866
kHz PWM is visible if you move (I find it easy to notice by rapidly moving my eyes left to right) but for the most part it's not noticeable. But even fluorescent lamps flicker at 120Hz (just look at a signal from a phototransistor) and are hardly noticeable in everyday life. Again, plenty of LED lights use rectifiers without filtration caps and are not very noticeable.

I have a bunch of chips im trying to communicate with via SPI by chaining all the CLOCK/DATA lines together and hitting each chip-select via a mux. The SPI chips are all active-low, except one. The fucking 74hc595. That fucking piece of shit.

Anyway, so I made a little inverter using a 2n2222 transistors and 2 resistors. I tried it on its own and it works great, but as soon as I wire it into the circuit with the ICs, it does nothing. The output always stays LOW no matter what I pass the input.

Any ideas?

>>1455305
Use larger resistors, and preferably a base resistor at least an order of magnitude larger than the collector resistor. 10k and 100k is what I'd use. Not that I know if that would fix the problem, but It's CMOS, so the lower resistances should be fine.

Getting a handful of 74HC14s would be pretty useful in any case.

>>1455040

WTF, dude, that's how a three-way switch is supposed to work. it turns the light on when the other switch is in the same (up-down) position as the first.

>>1454972

serial is the most obvious way to send data, but there's nothing wrong with parallel: just run 9 wires, 8 for data, and 1 for a strobe.

>>1455040

WTF, dude, that's how a three-way switch is supposed to work. it turns the light on when the other switch is in the same (up-down) position as the first.

>>1454972

serial is the most obvious way to send data, but there's nothing wrong with parallel: just run 9 wires, 8 for data, and 1 for a strobe.

>>1455311
>Use larger resistors

this advice is completely backwards. if the transistor is not turning on with a 2K on the base, it's certainly not gonna turn on when you *reduce* the current by 50x.
the problem lies elsewhere.

>>1455305
> The SPI chips are all active-low, except one. The fucking 74hc595

Are you sure you're using the 595 correctly? That chip doesn't have a chip select pin. Do you mean pin 12 RCLK? That pushes the shift register into the output D flip flops. The shift register takes in data regardless of its state. Also the action happens on a low to high transition. The bits you're putting into the shift register won't appear on the output pins if you just leave it high.

>>1455371
>the transistor is not turning on with a 2K on the base
Then you use a larger collector resistor to ensure that the saturation current is low enough to be achievable. But that isn't the problem anyhow since he's using 1k and 2k resistors, which are already fucking tiny for small-signal purposes.

>>1455305
Transistor inverters are very slow. Try using much longer pulses.
Also, IIRC '595 RCLK is edge triggered. Thus, you should be able to connect your "CS" line directly to it - except that you probably need to produce two CS pulses.

if i want to find out what value a 3 leg trimpot is regardless of the position the adjustment screw is in, do i measure the resistance of the left and right leg?

>>1455445
Yep.

Is this too much for a total beginner?

https://www.instructables.com/id/GamePi-Zero-the-Favorable-Emulation-Station/

>>1455375
>The bits you're putting into the shift register won't appear on the output pins if you just leave it high.

Ah, I was under the impression that it would, and an issue I had earlier made it seem like this was the case.

I'll get rid of the inverter and try debugging, as there must be a different issue. Thanks guys

What's the best way to bias a JFET that minimizes the effect of parameter spread to the greatest extent possible?

How do I get started developing for FPGAs? I'm more interested in using them for high performance computing simulations rather than embedded.

>>1455596
First of all buy one, then program it.

>>1455596
for HPC you can get pcie cards for your workstation that have one or more FPGAs on them.
https://www.xilinx.com/products/boards-and-kits/view-all-pcie-boards.html
https://www.dinigroup.com/web/index.php
not shilling for any of these guys I just know because I used to look into this stuff for hpc.

Nvidia also has gpu accelerator cards just for HPC, no video output.

>>1455608
>>1455610
But what about in terms of learning to program them?

>>1455615

>>1455615
verilog is great and easy to learn if you get parallelism.
http://www.asic-world.com/verilog/verilog_one_day.html

all of the ides will make you want to drink bleach. if i had to choose one, i'd choose to kill myself.

How do I find the right type of part on digikey/mouser/etc? I've tried using pic related and it works great, but it doesn't have anything to solder a wire to. I'm not sure how to find a connector like pic related but with solder cups or solder pins.

>>1455860

Honestly, the best I can tell you is that you have to REALLY know what you're looking for. As in, the exact name of the product line.

Finding connectors is a fucking nightmare. There's a billion different variations of each pin configuration, and there's no good way to narrow down what your looking for thanks to the fact that, usually, all you really care about are how they're meant to be mounted (PCB, panel, or wire-to-wire), how many contacts they have, whether they're locking or not, and how much current they can carry.

I _still_ haven't managed to find good, inexpensive, general-purpose connectors for the 2-5-ish amp range that covers my board-to-board, board-to-wire, and wire-to-wire needs. Closest I've found is mini-JST, which everybody and their mother wants to sell me with a wire already attached when I specifically DO NOT want leaded connectors.


Speaking of which, any suggestions from anyone? I use the regular, dirt-cheap 2.54mm headers and connectors as often as I can get away with and screw terminals for most everything else, simply because that's all I have that actually works and doesn't cost $1 per connector pair.

PowerPoles are pretty good for higher-power stuff, but either those have gotten more expensive since I last bought a box or I'm somehow not remembering correctly. Plus, they're a total waste if I just want to do something like plug in 50W motor instead of a 1kW+ load.

>>1455869
That's not good, because the manufacturer of that connector I tried just calls them 'modular contacts'. For some reason I think they're called leaf spring connectors but I'm not completely sure what the generic name for them is

>>1455860
your pic is of an SMD connector
made for Surface Mount it has solder pads on the bottom where it connects to a circuit board

in the search filter of your supplier's catalog
tic the box for "through hole" if you want to solder on the backside of a circuit board

>>1455886

>>1455886
I'm not putting the connector on a circuit board at all though. I'm using the connectors for a quick change battery thing; the connectors are placed in a 3d print rather than a circuit board.

>>1455916
it's common for manufacturers to mold their own housing, and just use the pin/spring components in their design.
another option would be to plastic-weld the connector to you charger base, and solder the wires where it would have been soldered to a board.. either pin or pad works.

post a pic of the battery you are charging

>>1455922
The wire I'm soldering to the connector runs for a few inches and pic related is on the other end. Being that the back of the connector only has a tiny point to solder the wire onto, the solder joint breaks way too easily to be usable. It'd be perfect if I could find a connector like the other one, except with more surface area to solder the wire on.

>>1455925
i won't ask why you are using 50amp wire to trickle 0.02amps into a battery, i'm sure you have your reasons.

>>1455931
I'm using the wire to connect the battery to the thing I'm powering; it's not for charging.

>post a pic of the battery

>>1455939

>>1453390
I’m doing computer engineering, same department and core EE/CmpE course but substitute emag, power, and upper level DSP with programming, architecture, and other low level stuff (could have done advanced DSP, would have helped since I work in software for signal processing, but oh well). Your intro EE classes will be the hardest and it stays constant from there. I’m in my 5th year. Just do 5 years, get an internship, and you’re good. You don’t want to rush an engineering degree (well any degree really) but it’s crucial to get work experience before you graduate.

>>1452945
I’m doing an embedded systems course this semester with an ARM mbed and add-on devices. Can anyone recommend an organizer case to carry it around in? The prof recommends a Stanley organizer, and there’s a very similar AmazonBasicscase, but I want something smaller that will fit in my backpack. The breadboard I’m using is ~8.5” x ~10” and has been a limiting factor.

I didn't pay attention to the "Image is for illustrative purposes only" warning and I ordered a load of film caps that have 15mm lead spacing when I need 5mm lead spacing.
They have tiny little legs too so I can't really bend the legs in and have the cap sitting off the board.
I don't really care about aesthetics so I was thinking to solder one leg in place and sit the cap vertically with some heatshrink covered cable linking the other leg to the through hole.
Does anyone have any better suggestions?
Ideally I'd just buy the right size but film caps are expensive bastards.
They're being used on the inputs to various op amp band pass filters

What am I doing wrong? Pic related is my arduino code. Basically I want to read data from a color sensor when I press a button.

I can detect button presses just fine if I comment out the color sensor lines, and I know the color sensor works. However when I put the 2 together the serial monitor freezes and shows no further text after I press the button. Even releasing it again will not get the "button NOT pressed" text back.

>>1456039
Here is how the wiring is set up. I can see that the color sensor's main LED is on as long as the button is pressed although there are no readings in the serial monitor. The serial monitor will not show that further readings after the first press even after the button is released.

>>1456048
Color sensor is an adafruit TCS34725

>>1456039
use interrupts senpai

>>1456034
Input Cs are mounted close to the board for a reason: you don't want antennas at that place. Don't fumble, contact your vendor and get the correct version.

>>1456034
with the wire you're adding some resistance and inductance, and making a bit of an antenna. For audio stuff it's probably not a huge deal, but I'd still rather get the right caps anyway.

>>1456034
dont listen to these negative nancies. it's entirely likely your inputs are gonna come from 4-foot long input cables, so an extra 3/4-inch wont mean dick all. i'd do exactly as you proposed except i wouldn't use any heat shrink coz there's nothing even close to touching.
>>1456065
>>1456071

>>1456089
Ah well, I've already gone and ordered some 5mm ones.
Found a range of Epcos PET caps for around 25 cent a piece.
The Vishay ones I had were about €1 each

>>1456048
>>1456049
what the fuck is Vih on color sensor?
Looked at datasheet and nothing even similar to that name

>>1456229
>>1456048
>>1456039
Just thought of it - if it's powering on color sensor - you should be hanged.

Leave color sensor powered on constantly and then see if it works.

>>1456229
Vin

If I directly attach the sensor to the +5 rail on the breadboard, the same place as the button attaches to it stays on all the time but no button presses are detected since the arduino thinks the button is pressed all the time.

>>1456229
>Looked at datasheet and nothing
Look again, it's on page 4.

What's the lowest-power way to wake up a microcontroller when a touchscreen is touched and/or when a person's hand moves nearby?

I want to build some programmable zigbee lightswitches/remotes with a touchscreen to display buttons/switches/dimmer controls. But I'd also like it to run off batteries, so I want everything to be powered down or in a sleep state until someone is actively trying to use the thing. Then when someone touches the screen (or, ideally, moves their hand near it), it should generate an interrupt to wake the microcontroller, which can turn on the screen and/or send commands over the radio.

So far I've been looking at resistive touchscreens, and it looks like I could wire one up with a comparator to generate an interrupt when the screen is touched. I'd prefer to have the remote wake up as soon as you put your hand near it, so you can see the controls on the screen before you touch it, but I don't know what sort of motion/proximity sensors I should be looking at for low power usage.

>>1456304
>I'd prefer to have the remote wake up as soon as you put your hand near it, so you can see the controls on the screen before you touch it, but I don't know what sort of motion/proximity sensors I should be looking at for low power usage.

A pushbutton connected to an external interrupt pin would be the lowest power, assuming you can power down the screen and other stuff.

>>1456308
>A pushbutton connected to an external interrupt pin would be the lowest power, assuming you can power down the screen and other stuff.
Well, yeah, but having to push a button and then touch the screen to do the actual controls would be annoying.

I guess I could scrap the touchscreen idea and just use hardware buttons/switches for the first version.

>>1456304
>it looks like I could wire one up with a comparator to generate an interrupt when the screen is touched.
Yeah, that works. There are even ready-made controllers for resistive touch screens which provide such interrupt. I think TI makes them, among the others.
You can use capacitive touch sensing ICs to detect nearby hand at reasonably low power consumption. Microchip also provides a library (QTouch) for capacitive sensing. If you use it, you need to wake up the controller periodically to make the measurement, though. Dunno how well QTouch actually works.

>>1453809
>asking god to help you fight himself
>2v2 cage match: you and Jesus vs the father and the holy ghost

>>1456304
google search: Livolo switches
I just installed hundreds of them in a rich bitch's house. They're waterproof glass, so you can install them in the shower. Compatible with most smart-home systems.

>>1455869
there are some ali sellers that specialize in connector lines. here
https://www.aliexpress.com/item/benis-in-connector-XDDD/32856578512.html

>>1455925
do like the pros do and make an itty bitty board to mount that little SMD thing on and connect wires to

>>1456007
bait boxes and cases are actually bretty gud
also start with a smaller breadboard or two

>>1456285
no, fool, separate the button and the color sensor. if you really must, turn on the color sensor via a separate output and give it time to start up before querying it

>>1456039
>What am I doing wrong?
>arduino code
you just answered your own question

>>1456039
>>1456350
or, better yet, use the sensor's built-in power maangement instead of your shit-tier button scheme that probably locks up the sensor with switch bounce

>>1456468
https://www.youtube.com/watch?v=-sTzLMqfxHw

>>1456473
>this is how arduino people use a breadboard
absolutely disgusting

>>1456475
kids today don't know how good they have it
we had to make our own bread boards

>>1456478

>>1456478
>>1456479
I want to do this

>>1453390
Do you want to be 25 with a degree or 25 with no degree?

Pick option 1. I'm 25 with a AA in biz admin. Total waste of years, going back in the spring for EE.

>>1456479
>those shooped burn marks
made me lean slightly closer to my screen for a few seconds

>>1456478
bullshit, that's Melba toast out of a bag

>>1452945
Is there a resource for getting an intuitive feel of general electronics? I feel like some people have a "grasp" that allows them to basically understand the circuit just by looking at it. Meanwhile I can use integrals and formulas to solve whatever but dont have a super concrete idea of basic concepts like voltage. It makes understanding circuits that contain a bunch of transistors p difficult and I basically have to brute force memorize various topologies. Also I'm constantly having trouble understanding how power supplies work within the circuit, ie. in terms of how loads affect voltage or current when you hook them up

I've tried with the water pipe analogy but it's never really clicked for me and kind of stops working when you get to transistors and other non linears

>>1456285
What the hell, how would pic related be always on. Recheck your wiring.
Also use something like 100k resistor for pulldown.

What now is happening - due to button bouncing during actual time when sensor is initialising it probably locks up. Some ICs do not take lost power during power on too kindly.
And since your sensor and probably code locks up, you can thank retards that wrote arduino core libraries and disabled watchdog.

Also before you read sensor check if it actually responds with tcs.begin(), maybe use it in a loop

>>1456473
>not even properly showing bouncing effect just some voltage dip which is way above high state threshold
>literally using delay in code for button debouncing
Entire video is just painful to watch

>>1456568
>I basically have to brute force memorize various topologies.
That's a big part of your "intuition" and there's no shortcut to it. Many of the commonly used circuit blocks were significant innovations at their time and it's not very likely that you'll "just get them intuitively" when you see them the first time.
That said, if you're having problems with power supplies and water analogies, then maybe part of your the problem is elsewhere.

>>1456568
https://www.youtube.com/watch?v=OGa_b26eK2c

>>1456568

a lot of it is simple pattern recognition. i can look at the circuit on the left and, in the blink of an eye, understand it completely coz i've analyzed it and seen it in action dozens of times before.

now, the kids today are using simulators, and such, that dont respect that standard topology for a 555 astable, or anything else, really. that leads to ugly scenes like on the right of the pic, which make you go back to square 1, where you're tracing wires and trying to figure what you're looking at. makes you wanna scream.

What is a good software for designing circuitboards? They all seem so clunky (KiCAD etc.) especially when adding new components.

>>1456600
>but kids these days
>muh 555
Bah. Shitty schematics are nothing new.

>>1456607
Good is in the eye of the beholder. I like Altium.

>>1456607

all PCB software was designed in the dark ages. if you want good, you have to write your own. as a bonus, you'll make millions and live on an island full of teen girls in short shorts.

>>1456607
KiCAD 4's library editor is indeed a clunky piece of shit, and the rest of the program kinda followed suit. KiCAD 5 has gotten a whole lot better at libraries and the UI feels a lot less "special-casey"
still, there's not a whole lot to be done about the fact that the components you want probably aren't in the library and you'll probably have to add them to your own private library. practice, I guess

>>1456624
Oh shit I just downloaded the new KiCAD and it's miles better. the old one was evidently designed and implemented by a bunch of autistic savants.

>>1456497
>2018
>no cnc laser toast

>>1456621
>all PCB software was designed in the dark ages. if you want good, you have to write your own
you don't get out much do you

there is pcb software that auto-routes your traces on upto 9 layer thick pcbs

there is circuit simulation software that gives you real-time circuit function as you add virtual components

>>1456666
yeah and the interface for that software is a human rights violation

>>1456666
What PCB editor is limited to 9 layers these days?
And he was referring to the UI.

>>1453390
Don't worry man, at this rate I will get graduating at 34.

>>1456691
People that do this for a loving learn the key board shortcuts, son. I'm sorry clippy wont design your arduino project for you based on how you mash your face on the keyboard.

I fucked up.
I have a pcb that has though-holes for a 16 pin connector which is being soldered there and during my try to remove it with my soldering iron, several pads around the holes got removed.... yeah I don't know how this shit managed to get unstuck from the board.
Now I have to connect them to their respective pins on the surrounding components.
Does anyone know how that slim wire is called that has a transparent insulation and is used to do this kind of bypasses on pcbs?
I've seen louis rossmann use it frequently.

>>1456723
Magnet wire, enamel wire. Sometimes he just uses solder wick if they are very close

>>1456723
Enameled wire, you can find exact spec for wire rossman is using in his shop.
In general any wire will do just at >32 AWG it's easiest to use thin single strand wire with easy to remove insulation.

>several pads around the holes got removed.... yeah I don't know how this shit managed to get unstuck from the board
Probably a lot of heat and not needed force to remove component. If you do this a lot, I suggest investing a bit into quality solder removal tool.
Otherwise you have to deal with it occasionally. Other method I use for parts which I'm not planning to reuse - cut legs, desolder remaining legs (much easier) and put new component. If it's cheap job, I might just bend through hole legs into something resembling SMD legs and just solder on remaining cut legs.

>>1456723

enameled wire is most definitely the wrong type, coz it's a huge bitch to strip. the correct answer is 30AWG wrapping wire.

>design a simple board drunk
>literally three of the four device footprints are wrong even though i double checked them
at least i didn't put the resistors backwards

>>1456731
>>1456732
>>1456741
thank you for the replies.
I think that I will go for the enameled wire, despite being a bitch to handle, because it's on an embedded device with a tight enclosure and I am afraid that wrapping wire might be too loose and thick for that application.
a 30 awg or a bit smaller enameled wire might do the job just fine.
and for the record 30 awg = .255 mm
I have some dead coils around here and those will donate the wire for that purpose.

I'm trying to learn the ohm stuff.
I burned several diodes now I'm working with tinkercad. Nothing works like I expect it to. I don't understand how Ohm's law translates to the diodes and resistors I connect.
Yes, I didn't have physics class in high-school.

How do I even use multimeter to check my calculations?

>>1456849
>does a 9v battery correspond to a 12v source
>does a 600 ohm resistor correspond to a 100 ohm resistor
I'm gonna go with "no"

>How do I even use multimeter to check my calculations?
Put it in current measuring mode and wire it in series with the rest of your shit, like shown in the bottom pic

Ask a more specific question if you want more useful answers

>>1456864
I meant the general way of connecting stuff.

>more specific question
I don't even know what I don't understand at this point. It's all magic.

>>1456867
Ignoring the extra meter and what the other anon pointed out, yes, the bottom pic is equivalent to the upper pic.
The calculations in the upper pic are correct in principle, but most LEDs need more than 2V and if you use two blue and one yellow LED like in the lower pic, you can expect the current to be significantly less than 10mA with a 600R resistor.

>>1456870
The picture with calculations is from a bigclive's video, I was trying to copy stuff he writes to test the,

>Ignoring the extra meter
How else can I see what I'm actually doing and what are the values?

>>1456873
>How else can I see what I'm actually doing and what are the values?

we need a "beginner's electricity" general thread so this sort of topic can be discussed apart from actual electronics questions.

>>1456873
>How else can I see what I'm actually doing and what are the values?
It's not wrong. It's just different from the upper pic.

>>1456651
that is probably true. there's something to be said for having a budget and an organization behind you

>>1456723
devices with lots of pins don't take well to being desoldered with just an iron. hot air is a great tool for this sort of work

>>1456788
wire wrapping wire is pretty good for this sort of thing, actually. otoh if you have Kapton tape you can run a bare wire and use the tape as insulation against bare terminals you don't want it to touch

>>1456876
agreed, please for the love of god someone do this

What are relay failures like, and can there be a half functioning relay or something like that?
Please bear with me

>headlight switch off = brake lights and blinkers work properly. the daylight running lights are on

>headlight switch on = right side brake lights no longer work and the blinker flashes fast like its failing. daylight running lights turn off and the heeadlight bulb comes on.

When the temperature outside is COLD, the car starts with its headlights on and brakelights not working. As the temperature warms up or the car warms the engine bay enough you will hear an audible click that sounds like a relay and the headlights will turn off, daylight running lights come on and the brake lights work properly.

When the temps outside are warm or hot its as if the headlights are off and the brakes work fine. You have to physically turn the headlights on for the lights to fail.

This has been going on for a few years now, ive made several diy threads, ive made several /o/ posts, ive asked forums and I havent found a good answer. I just started going to work at 4:30 in the morning and have already gotten pulled over twice in a month because of it.

Does this sound like a relay problem or is there anything I can really look at? Ive replaced the bulb socket like some people said and it didnt fix anything.

>>1456499
>toast out of a bag
>out of a bag
>a bag
P.S.-Why's reCaptcha so fucked?

>>1457019
>P.S.-Why's reCaptcha so fucked?
Works on my machine

>>1457019
you'll eat it and you'll like it, friendo

>>1456478
>had to make our own bread boards
you goofed - it's toast

>>1457007
all that text and no indication of make, model, and year of vehicle

>>1457007
short somewhere in a wiring harness. take it to a mechanic, since you clearly lack the ability to troubleshoot it

>>1457109
its a 99 chevrolet s10

>>1457111
I dont understand why a short would make the headlights flip on and off from a temperature change.

>>1457123
http://www.chevytalk.org/fusionbb/showtopic.php?tid/167244/

>>1457153
Be sure to read the whole page.
The actual problem is in the last post.

>>1457107
it's toast after it goes in the reflow oven but
toasted bread is still bread

>>1457166
>does this resistor look burned to you?
>yeah man, it's toast...

>>1457007
it sounds like a problem with a ground in your cars electrical system. your negative batter cable should be connected to the engine, and secondary smaller ground wires from the cable should go to the frame, and to the body of the car. On trucks where the body is mounted on rubber bushings, and the engine mounted on rubber vibration mounts, they are isolated from ground.

>>1457170
i propose a toast
in memory of our fallen component
Vive la résistance!

I need an arduino to sense when it's near a magnet. Is this the part I should use?

>>1457180
reed switch
closes (or opens)
in a magnetic field

>>1457181
This, though it isn't as sensitive and might activate from shaking(?). A 50c hall-sensor will be able to measure fluctuations in the Earth's magnetic field and has no moving parts.

>>1457170
carbonification

>>1457182
https://www.gillsc.com/newsitem/45/5-reasons-choose-induction-over-hall-effect-sensors

>>1457181
>>1457182
I'll try both, it's for a joke and they'd probably recognise a reed switch.

>>1457188
>they'd probably recognise a reed switch.
smd reed

>>1457186
these only work with AC or at least changing magnetic fields AFAIK, not DC. So they'd be pretty bad at dealing with permanent magnets. I'd only use them for motor speed sensing, or that sort of thing.

>>1457196

nah, dude, they use an intelligent controller to generate the waveforms and take the measurements. so the output could be either an analog voltage or a pulse stream, or whatever the maker has programmed it to do.

>>1457200
Use them with an integrator? I guess that could work, about as accurately as inertial navigation, but the point about "hall sensors are effected by EM interference" equally applies to induction sensors. Kind of a biased piece if you ask me.

Induction Coil Magnetometer

>>1457200
Oh they actually put current into the coil and measure the feedback. Like a guitar pickup. But that will equally sense changes in magnetic permeability as changes in magnetic field.

Hey, wiring noob here.

What is the best way to bypass/solder across the R7 resistor marked in the image?

It's the trunk actuator output in the central locking kit i installed in my car, but it only puts out about 10 mA which isn't enough to activate the relay that will send power to the trunk actuator. Measuring before the resistor shows about 1 A of output which will work.

The soldering iron I have is a bit to big to accurately get in the tight space and solder a wire before and after the resistor, would it work if I just melted some solder across the resistor, covering it?

>>1457276
>would it work if I just melted some solder across the resistor, covering it?
when you get it that hot the resistor will fall off
put the blob across the solder pads
be careful to not affect the adjacent component

>>1457276
>melted some solder across the resistor, covering it?

as you attempt that, the resistor will come off and get stuck to your soldering iron. but that's a good thing. you then shake it off your iron, keep it for reference, and put a blob across the two free contacts. trying to bridge over it would be much harder.

alternately, you can put a blob from the left of the resistor to the second pin from the right on the white connector, but your clumsiness will surely scorch the white plastic a bit.

for the record, i'm not confident in the wisdom of making this mod, at all.

>>1456723

>>1457019
>Why's reCaptcha so fucked?

shadow banned by google sjws

>>1457294

>>1457301

there has to be a better way. i don't breadboard most of my shit just because it's so annoying.

>>1457319
https://www.partsim.com/simulator#

>>1457326
i use multisim, but you can't trust it with non-ideal ics.

>>1457319

consider using good old-fashioned telephone wire instead of chink meme wire.

>>1457399

If you have that much confidence in the circuit design to waste all that time on those perfect bends, why not go ahead and solder a proper circuit and avoid the breadboard issues.

>>1457404
>to waste all that time

autism is a beautiful thing when done correctly, anon.

>>1457404

coz that would be stupid.
just like your question.

>>1457284
>>1457285

Thanks guys, I managed to desolder and remove the resistor and bridge the gap with some solder, it's working perfectly so far!

I want a circuit that takes two PWM signals and passes on the "stronger" one. This way, I could have the fans in my computer be controlled by both the GPU and the CPU at the same time, simply running the fastest whichever board wants them to. Pic related I came up with, however, that solution assumes the same peak voltage for both input signals.
Any obvious improvements to be made?
An entirely different approach?

>>1457469
Now I realized if I feed both buffering opamps with low enough voltage, resulting signals will be clamped down to that, thus eliminating the issue with possibly different peaks.

>>1457469
I'd think the GPU would have a better idea of the board/chip temperature from the temp sensors it has on board. Just let it do its thing.

So basically I've been watching potheads' videos on how to make an LED growlight lamp, and nowhere have they discussed a fairly simple question that I had.

If I were to chose an LED driver of lets say 100V voltage output with 2A current, but decide to wire it to a single COB with 50V in hopes to have it generate 100W of both photon and heat energy, would something implode? For whatever reason, I feel like a dumbass for asking this here.

>>1457516
You're not getting it, I want the GPU (or CPU) to control case fans. That's also why I'm buffering the signals before smoothing - not to fuck up the GPU's own fans on the same PWM line.

>>1457523
Your motherboard software should already do this.

>>1457521
Are you asking what happens when you attach a 50V module to a 100V source? Fucking summer, I thought it had ended.

>>1457524
It does, with the temperature readouts it has access to. Imagine some program fully loading the GPU while leaving the CPU chilling - GPU fans ramp up, motherboard-connected case fans dont however, although it would be good if they did. And that's what I'm looking to improve.

>>1457536
Your motherboard almost certainly has an ambient air sensor, make that more sensitive. My brothers mobo actually came with 4 extra thermistors and hwles like wtf do i do with these. I dunno, its a pretty tiny box anyway and you can move a lot of air really easy as is.

>>1457538
All that comes down to variants. Now that you know what I'm trying to achieve, can you perhaps share insight on the circuit I have posted?

>>1457555
run the op amps as comparators instead of voltage followers, feed both - leads with a resistive voltage divider
then add a resistor before the capacitors (100k or so)
add some hysteresis to the op amp driving the relay, which might entail a voltage follower on the + input
then it should more or less work

>>1457568
Thanks, gotta go now but will look into this tomorrow

>>1457523
Fan Contoller

>>1456034
what is that, a filterbank or something? synth stuff?

>>1456568
I find a lot of it comes from seeing a topology and recognizing its place in context of whatever the circuit is supposed to do..
looking at a schematic is one thing, looking at a board is more difficult.

>IC's and small caps. most are probable decoupling.
>transistor stages in an amplifier, lots of caps. ac coupling( or dc blocking, if you prefer).
>pico range capacitors near opamps, low pass filter in the feedback.
etc.

to me, its all about having seen something like it before in detail.
I've worked on older maritime equipment for years, while messing with guitar amps/effects and synth on the side.
If you gave me something I'd never worked with or even have a grasp of the internal functions of, I'd struggle.

>>1456849
fuck around in falstad. decent websim.

I made this for you:
http://www.falstad.com/circuit/circuitjs.html?cct=$+1+0.000005+10.20027730826997+50+5+43%0A162+96+112+96+160+1+2.1024259+1+0+0+0.01%0A162+96+160+96+208+1+2.1024259+1+0+0+0.01%0A162+96+208+96+256+1+2.1024259+1+0+0+0.01%0Ar+96+256+96+336+0+600%0AR+96+112+96+80+0+0+40+12+0+0+0.5%0Ag+96+336+96+352+0%0Aw+96+256+144+256+0%0Ap+144+256+144+336+1+0%0Aw+96+336+144+336+0%0A

>>1452945
I am doing some good things.
if(true)
return big;

>>1457399
That's a nice breadboard model, anyone know where to find one like it? Though I hope it accepts square header pins.

>>1457521
>>1457535
Well if it's a 100V-max constant current module (which for an LED driver is somewhat likely) then as long as the set current isn't above the maximum for that COB (and the voltage is able to go low enough, which is likely) then you should be fine. But slap 100V across a 50V LED and it will burn itself out in far less than a second by inadvertently putting too much current through it. Look at the Shockley diode equation if you're interested.

Redbull me on low light camera boards like pic related coming out of china on eBay:

https://www.ebay.com/itm/Sony-IMX322-NVP2441-Starlight-Low-illumination-HD-1080P-AHD-Module-CCTV-board/322609593382

Do these actually work? 0.0001 lux if true means I can see without IR LED illuminators at night. Where do I get the lens? There has to be something I'm missing.

>>1457407
he's right you know
breadboards are for babby level circuits
what you're doing is much better suited to perf board

>>1457762
https://www.youtube.com/watch?v=bci7Gi05BNc

>>1457773
noice generic SOIC boards

>>1457778
I guess they're the SMD equivalent to perfboard.

>>1457775
I plan on inserting the camera into an airshit dummy NVG shell to make a ghetto ass version of the X27.

>>1457785

>>1457792
Half-pitch perfboard? That's pretty cool looking stuff, but my high-current diode package leads probably wouldn't fit in those holes.

>>1457816

typical insecure dude, always taking the opportunity to brag about his supposed girth.

>>1457825
>size doesn't matter

>>1457850
My penis is for waste disposal.

>>1457850
this image but unironically

do joule thieves output sine waves?
My friend and I aren't sure
http://tinyurl com/yaypharh (falstad circuit link)
this circuit outputs a sine wave but I'm having trouble reconciling the fact since it's a DC circuit

>>1458062
It's basically a blocking oscillator. They produce short pulses, often with somewhat weird shape.

>>1457850
>posts doggo maymay
>can't into rubbing your leg against something to get the job done
oh no, it's retarded

>started Digital Fundamentals this week
>out of 10 students I'm the only one who rented the required book vol 12
>one student found vol 10 and shared it with the class
>instructor decided to teach course with vol 10 instead of 12
I feel kind of fucking cheated.

>>1458307
Can't you return it? Just say you switched classes.

Yo I'm poor as fuck EEE student and I've always wanted to mess about with electronics but can't just spend on random shit. I tried asking recycling sites about electronics but they said fuck off before I could explain anything. What do?

Reposting this from sci
New to EE and I really interested in radio frequency and microwaves and might do it as a concentration instead of control systems. What are materials I can consume? Already picked up Pazor's microwaves. Any tools I should know how to use or simple projects?

Also heard if you're going to projects with radios I should get a licenses. What level would I need?

>>1458335
>>1444577 would be the place to look to for stuff involving ham licences and such. You'll only be able to transmit on amateur radio bands, for which pic related will be handy. Across the bands there will be different levels of practicality for different types of antennae/emitters, so I'd make sure to take a good look at existing solutions. Microwaves require specialty circuit-building knowledge, so watch out for that.

>>1458347
Speaking of circuit building are there any spice that is FOSS? I heard KiCAD can do it but not sure how and good it might be

>>1458351
KiCAD is shilled a fair bit here, it's safe to say it's decent. Perhaps not as user-friendly as others though. If you're with an education facility you may be able to get Eagle free, though it's not open-source. I've briefly tried both but always go back to Gimp and a sharpie.

>>1458360
Thanks for responding, it's been helpful. But one last question, SDRs. Going into learning about, I thought GNU Radio was supposed to be FOSS alternative, but apparently it can operate as a receiver with Gqrx. Anyone have any experience with this?

>>1458365
I bought one of those $20 TV SDRs and it worked fine as an receiver with GQRX. Apparently the higher end models can transmit as well, notably the HackRF One and at least one BladeRF model. AFAIK GNU radio is just a basis for writing software to interact with SDR hardware, and chances are GQRX (and similar software) is partially written with it.
>Gqrx is an open source software defined radio receiver (SDR) powered by the GNU Radio and the Qt graphical toolkit
From the GQRX website. But an anon was complaining about it not doing full sweeps in the ham thread like the windows software does.

Though personally I'd stick to more analogue methods because there's latency in all the DSP and you have to rely on software that you don't really know how it works, lest you dive into GNU Radio yourself. Time-to-digital converters are something that might interest you, they're used for laser range-finding and you may find a use for them as part of a CW/digital receiver. They come with very impressive time resolutions.

>>1458374
I never been on /diy/ before and you have been great, thanks!

>>1458374
>there's latency in all the DSP
and this matters why?
really, it's not so bad to just string together a receiver in GNU Radio Companion. it's pointy-clicky easy as long as you have some understanding of DSP and radio
>Time-to-digital converters are something that might interest you,
"a little understanding is a dangerous thing."

>>1458351
I found Qucs
Never used it, but anyone with experience might quickly assess some problems with this? Many some important features that other spices have.

>>1456039
Make sure the UART pins aren't also being used by your button or color sensor. I.e. nothing on pins 1 or 2. Or 0 and 1, I don't remember how they're indexed.

>>1456450
Why do people on this board hate on Arduino? Is it not DIY enough?

Does anyone have a good resource for cooling SMD/SMT components? Heard it's not good to use a heatsink in the traditional "on the chip" manner.

>>1458351
LTSpice is GOAT spice, not open source but suck it up

>>1458398
>Why do people on this board hate on Arduino? Is it not DIY enough?
it stands in your way when you need to start doing anything advanced. you're not learning to microcontroller, you're learning to arduino. you're not learning to talk to off-chip peripherals, you're learning to call libraries. and so on. as soon as you decide to program a system not supported by lolduino, you suddenly find yourself a brainlet awash in a strange sea
also, FTDI USB-serial interfaces are gay, which has only recently been sort of starting to be addressed by the platform

>>1458399
http://www.analog.com/media/en/training-seminars/tutorials/MT-093.pdf
generally, SMD components dissipate heat through the leads/slugs to the board they're attached to, which can be improved by adding copper area and vias, though some thinner packages consuming lots of power (think SoCs) can make good use of heat sinking on their top sides

What soldering iron do you have?
Do you like it?

>>1458422
love it

>>1458414
It is painful to watch sometimes, as an arduino user spends two weeks building something that in the end has the same functionality of a .35 cent chip that was designed in 1977. However, I do recognize that sometimes having the added capabilities of an arduino could come in handy.

For example, fixing your can opener that has a broken switch. You can replace that switch with another switch and it will work again, but if you replace the on off switch with an arduino it opens the door for taking advantage of that can opener in ways that were previously impossible.

Driving home from work, you could say to your phone "hey can opener, open the can" and when you get to your kitchen the can is opened, and ready to make your favorite soup.

So don't hate on the arduino users, once in a while they make something useful.

>>1458422
Got it in 1987 never had a problem with it.

Anyone know a source for "private theatre" type glasses that seemed to be common before 2010? I would prefer if they can take an RCA input.
I've seen these:
https://www.instructables.com/id/Glasses-mounted-video-display-to-one-eye-turn-yo/
https://www.adafruit.com/product/1452

I want to extract the miniature screen assembly from them.
Or better yet a source for the screen assembly itself?

>>1458307
I uhm. I used to teach - like 10 years ago, and I was blown away by how few people bought the books. I don't understand it at all. I'm assuming this is more than a "Trend" and is basically the norm these days.

>>1458458

https://www.digikey.ca/products/en/optoelectronics/display-modules-lcd-oled-graphic/107

If a LED says it operates at 12V and i connect it to 12V why do i still need to use a resistor aynway? I thought resistor was when your supply voltage is more than the LED's operating voltage is

>>1458471
12V is the voltage drop, led's will draw as much current as they can source at this voltage. You dont want that because it will quickly overheat and die. Adding a resistor reduces the voltage across the diode slightly, pushing it to a point on its IV curve where the current draw is limited to something sensible.

>>1458471
You don't need just a resistor, you need higher voltage too.
Resistors and other current limiters are used, because when you reach LED's turn-on voltage, any further increase in voltage raises the current very quickly, up to the point where your LED burns out. Count in the manufacturing tolerances and the temperature coefficient of the LED, and your constant voltage drive will be unstable and unreliable. On the other hand, if you use a series resistor and the voltage drop in it is sufficiently high in comparison to the LED forward voltage and the power supply voltage variations, the current and the LED brightness will remain relatively stable.

That said, some high voltage / low current LEDs work reasonably well with constant voltage drive. That is, their current increases relatively slowly when voltage is increased.

>>1458471
What did your speaking LED say when you connected it to 12V?

>>1458468
Already checked there. I'm specifically looking for whatever tiny HD screen they use.

>>1458467
publishers have tried to maintain the extravagant lifestyles they enjoyed when books were a thing, despite the falling sales and lack of interest in bound or paperback termite snacks, increasing textbook prices by more that 3000% in the decade since you were teaching.

If that wasn't enough they change a few words each year, to peddle a "new revised 135th edition" and some Universities and professors are happy to take bribes and kickbacks from the publishers and then insist that their students take out loans to pay for new books each year, trying to force new sales and render used books worthless.
couple this with the 5000% increase in tuition over the last ten years, and it isn't hard to understand why 90% of today's students are prostitutes, porn stars, etc.

>>1458480
>>1458479
I see. I got this 10W LED from chinks and it's literally just a white plastic square with some yellow paint in the middle. There are no instructions on how to use it, except some broken sentence that says to put the led in series with 12V DC and 1.5ohm resistor.
Do i need any cooling?

>>1458492
Of course, and a good thermal contact to the heat sink.

>>1458486

there is a lot of truth here, but dude, you need some exaggeration therapy

>>1458504
https://www.lib.umich.edu/files/SPOTextbookBackground.pdf

>>1458521
the average cost of college textbooks has risen four times faster than the rate of inflation over the past 10 years. That has caused 65 percent of students to skip buying required texts at some point in their college career because of a lack of affordability.

The main culprit? Textbooks bundled with "access codes" that expire at the end of the semester. These access codes largely force students to buy books at retail prices at campus bookstores and render the texts worthless in the resale market.

https://www.cbsnews.com/news/whats-behind-the-soaring-cost-of-college-textbooks/

I need to solder some 1206 SMD LEDs to a very thin (1mm) wire and I don't have the money to drop on a Hakko station and a tip. Would this iron be okay? The tip looks pretty small. I don't need it to last for that long, just long enough to attach some surface mount LEDs for costuming purposes
https://www.amazon.com/Weller-WM120-120v-Pencil-Soldering/dp/B0000WT586

>>1458525
Thankfully, these crooked publishers and their co-conspirators will soon be bankrupt.

What's your go-to way to power little portable projects?
I see these batteries a lot but I've avoided making battery charging circuits, don't want to be responsible if anything burns down. It'd be good if there were a little board I could plug the battery into, get 5v out and plug a micro usb in to charge the battery when needed.

>>1458531

a 12W soldering iron? you best be joking. 20W is the smallest you should ever consider for any job. get the WP25 along with a conical tip (to go along with the 1/8-inch screwdriver tip you get bundled).

if, by some miracle, you find the thing is too hot, you can always dim it down. but you cant go the other way if you have a frustrating, i-cant-get-even-get the-solder-to-melt, weak-ass 12W iron.

also, being a Weller, and being blue, means it'll last 20 years.

>>1458572
>It'd be good if there were a little board

there are a thousand types of such boards available on ebay, alibaba, and (gasp) sparkfun.

>>1458572
>It'd be good if there were a little board

there are thousands of such boards available on ebay, alibaba, and (gasp) sparkfun.

>>1458531
The WM120 is a good quality iron and 12W/800°F is (more than) enough for SMD, mine has 8W and also works well. I use 0.5 or 0.7 mm flux core solder wire. If you want it cheaper consider the 'USB' soldering iron plus a 5V/2A charger.

>>1458639
Wait, but the melting point of non-lead solder is usually around 300-450°F, and this iron heats up to 800°F
>>1458662
So it does get hot enough to melt non-lead solder?

>>1458670
>hot enough to melt non-lead solder?
Don't know, I use traditional Sn60Pb38Cu2 3% flux solder wire that melts well below 200°C/392°F.

>>1458531
have you considered using conductive glue?

>>1458670
>Wait, but the melting point of non-lead solder is usually around 150-230°C, and this iron heats up to 425°C
fixed that shit
if anything, that iron might be a tad hot, even for SAC305. work very quickly and hold everything in place with some sort of jig or alligator clips. also use a liquid or paste flux

>>1458532
>thinking IP capitalists could even exist within a free market
>thinking a large portion of that money overpaid for course materials isn't going straight into hookers and blow for legislators
if anyone wants to do the world a solid, go Charlie Hebdo on Elsevier

Where the hell do you guys go for your soldering stuff? Is there any brick and mortar chain type place? I have been checking out a handful of electrical supply stores and they’re all a handful of Klein tools and a bunch of light switches. City Electric, World Electric, Graybar... I guess RadioShack used to be the place to go. F.

At least one of them had this line splitter.

>>1458572
>It'd be good if there were a little board I could plug the battery into, get 5v out and plug a micro usb in to charge the battery when needed.
That's called a power bank.

https://www.ebay.com/itm/2in1-Charge-Discharge-Board-Module-DIY-18650-Lithium-Battery-Power-Mobile-Bank-/172737275327?_trksid=p2349526.m4383.l4275.c10#viTabs_0
^^ 99¢ ^^

>>1458728
a lot of local places are little mom and pop stores that get spread through word of mouth. keep looking. pic is near me.

>>1458730
no, it's called a battery charging module
>>>/g/ pls go

>>1458728
none of the B&M stores in my area will serve tripfags. sorry not sorry

>>1458733
It’s cool, I hide my power level when it comes to that.

>>1458731
Maybe I’ll ask the mechanics at my work because I don’t exactly hang out with a bunch of computer geeks.

I asked dude at the electric place who would have soldering stuff and he told me to go to the plumbing supply store and I’m like “I aint tryin to braze pipes mayne!”

What about like hobby shops or audio places?

>>1458731
Damn I just googled it and there’s one about 45min north. There has to be something like thay closer to me.

That’s exactly what I’m looking for. I remember my dad bringing me into a place like that with bins full of random connectors and fuses and whatever the hell. The places I’m going to are all like dudes ordering conduit and wire.

Ooh I think I found a place. Retarded hours like the rest of them though.

>>1458732
>called a battery charging module
Until you add the battery - as the poster described.
It then becomes a power bank
>>1458732
>>>/g/ pls go
No.

>>1458790
>tfw X10 isn’t a model number
I was wondering why this 12” fan was reading 6A and how my 7.5A impact was running at 30A+ without tripping the 15A breaker.

This thing is fun. I never understood electronics but thanks to a free meter from HF and /diy/, I’m slowly understanding things.

>>1458730
Well ignoring terminology that model is for an 18650, meaning it will probably try to put way too much current into a piddly 0.5Ah Lipo, lest it adjusts for ideal dV/dt.

>>1458846
not a big problem, just change the current programming resistor on pin 2

I'm trying to do some DSP on a PIC24. I've got a big 2D array lookup table of const floats. I'm getting an error that the size of the array is too large. When I make it small enough that the project compiles, the program memory is only 21% used. How can I use that other 79% to hold a bigger lookup table?

>>1458858
use a processor with something better than 256-word pages
or divide your const arrays into pages at the C level

>>1458852
Ah that's good.

>>1458859
The array is 50*122 floats at max. Why is a 256 word page the limitation?

>>1458876
on the PIC16 it would have been because indirect jumps for RETLW couldn't cross pages very conveniently and couldn't contain more than 255 members in any case. I don't know noteeng about no PIC24 but I still offer the general principle of adding a level of indirection to help out the retarded compiler: what if you split the arrays into fifty, one-dimensional 122-member arrays, and use a one-dimensional 50-member array of pointers to those values?

>>1458886
I'll try it out tomorrow, thanks. Pointers pointing to program memory is generally allowed, right?

>>1458414
Didn't see your respnose about the cooling, thanks.

>>1457469
You want to pick the one with the larger duty cycle?

Find your RMS voltages. Divide them by their peak to peak voltages if cpu and gpu amplitudes are different. These are the inputs to an analog comparator that controls an analog mux. You may want a buffer if the output is a splitter to multiple fans.

Then again I am out of practice and fucking stupid.

>>1458890
I would wonder how the hell they could make most of C work if it weren't allowed
sure, as far as you're concerned it's your read-only data section

>>1458916
you really just need to lurk more and stop overcomplicating every fucking project that comes through here

>>1458480
good post

millenials think LEDs are light bulbs. The D in LED stands for Diode.

>>1458945
>millenials
You mean baby boomers

>>1458644
>>1458730
https://www.youtube.com/watch?v=Fj0XuYiE7HU
Something like this, overcharge protec, overdischarge protec, 5v boost

I'm building some sim rudder pedals using hall sensors each axis and I want to have some software calibration functionality built in.
Idea is to center the pedals and then press a calibration button to store those center positions, and also maybe have functionality for setting up deadzones and sensitivity via some pots—rather than having to do all that in windows.

So should I use EEPROM or microSD for storing the calibration, deadzone, and sensitivity data? Assuming the data is read daily and new data is written a few times a week, will EEPROM degradation be a concern? If I use a microSD then I only have to replace the SD if bits start flipping right?

I'll be using a Teensy 3.5 / 3.6 for this project, has both microSD slot and integrated EEPROM. Looking at storing 6-12 int vars, so storage space isn't going to be a problem; I'm more concerned with memory longevity.

>>1458975
Often joysticks will have that sort of functionality freely available via whatever simulator/game is using it, or through software made for that joystick. There are joystick ICs that you may be able to find and use without troubles, some of them may have calibration software. I wouldn't jump to a multi-purpose MCU until you've looked at those options.

Regardless, both forms of memory should have ample longevity for this purpose, though the EEPROM won't have any connection issues that the SD slot may have. Is bits flipping an issue people ever have with these things? You could always just store a hundred of each variable appropriately stored in a binary format such that a bit flip will just change a single number, and take the mode of the lot if that's what you're concerned about.

>>1458975
hall effect sensor (old computer mouse with a ball)
optical / laser sensor (newer precision mouse)

store your calibration in the PC that you plug your mouse into, not a prom in the mouse

https://www.youtube.com/watch?v=SXQfT7c-9rU

>>1458532
>Textbooks bundled with "access codes" that expire at the end of the semester.
what? does the book set it self on fire after that or what?

>>1458572
unlike lead batteries i am pretty sure lipos can be charged with one steady cycle, and all you have to do is turn the juice off when the battery reaches certain voltage

How about frequency modulated IR signals emitted and received by all the light bulbs in your house that connect your smart fridge and juicer to your modem with no need for wires?

>>1459006
no

>>1458999
most serial flash memories are rated for 100k writes per location, unlimited reads, which should be many years worth. since you have ample space, you might consider allowing for multiple configurations of deadzone/sensitivity. also maybe just store the center calibration in RAM if it's that prone to drift
>pots
wait, if you're using an analog input here, why would you need to save it?

>>1458975
Even crappy EEPROMs can take 100k writes per position. So no problem if you're updating the memory only couple of times per week.

Rudder pedal anon here.
I think I'll write the code and see how much space the SD library uses and then consider EEPROM if I get low on program space (not likely) or if the SD library gets in the way of some other hardware operation (e.g. USB data speed).

There are several reasons for doing all the calibration onboard: No need to reconfigure if the PC / game decides to reset my settings (updates + USB driver fuckups have caused this so many times in the past it...). All the PC needs to do is read whats coming from the board, and still works if I swap computers. It's a programming challenge, which I'm all about.

>>1458999
I picked Teensy because 13 bit ADCs, great HID features, arduino and arduino compatibility. I've used the same board to make other HID stuff in the past. Its overkill for a simple project like this, but I like having plenty of room to add features / code later.
Thanks for reminding me about storing multiple of each variable, don't know why I forgot that one.

>>1459033 cont.
Damn character limit...

>>1459001
Not making a mouse
>hall effect
>ball mouse
Uh, bud... Ball mice used slotted disk optical encoders.
And to clarify I'm using analog hall effect, not schmitt trig'd.
>optical sensor
Precise, but not applicable here.

>>1459025
>>1459011
Yeah, 100k would last a long time if I only write on power-down if a variable has changed. Not much experience with EEPROM so I didn't really know what to expect. Good idea about storing multiple configs—I'll try it, maybe 4-5 onboard profiles with LEDs to indicate which is selected / being saved to.
>pots
>why would you need to save it?
Lol, it's almost as if pots remain in the same position when powered off... I feel dumb

>>1459034
I'm not your bud, pal
As I said "old ball mice" used hall effect sensors with a magnetized iron ball. In theory the no contact ball system was intended to be an improvement over the contact variety because the ball had a tendency to collect dirt which greatly affected performance. Surly a layer of dirt on the ball would not affect the magnetic sensors...LOL. Instead, these mice tended to attract staples, paperclips, and rust chips.

I'm well aware that you are not making a mouse.
My cyclic, collective, and rudder pedals use linear position sensors. I was saying that your hall sensors are problematic.

>>1459034
I'd use optical encoders personally. If those resolutions are insufficient, for a continuous encoder hall-effect is probably better than a potentiometer, but a resolver may be better than that. I very much doubt you'll be using anywhere close to all 13 bits of that ADC though, your bar/pedal(s) will move perhaps ±15cm at either end, the 13b resolution for which would be 37 microns. The flex in the bar itself will be orders of magnitude larger. 8 bits of ADC gives you a 1mm resolution, which while it could be a little on the small side should be sufficient. 10 bits would be fine for this. But use a rotary optical encoder and you should be able to obtain resolutions as good, with the right use of leverage/gearing.

>>1459042
>>1459048
MFG crosswind pedals and the Warthog HOTAS—both incredibly popular and worth ~$400 each use hall effect for every axis. I know money doesn't always == quality, but this is a proven technology.

I looked into linear pots, but can't justify spending $90-$400 on a single component that will wear out over time, when the entire rest of my BOM is under $100. Good hall sensors go for <$10 a piece.
The only wear on a hall assembly is the die itself breaking down due to current flowing through it (or possibly bearings depending on the setup)—i.e. no perceivable degradation within the product's lifetime. A rotary pot with filtering and an 8 bit ADC would /work/, but high precision means more flexibility and easier filtering in software.
Also hall sensor assemblies for this application require the fewest moving parts aside from linear pots.

Never heard of a stick or set of pedals that used encoders. Analog is king here.
Thanks for the advice though fellas

>>1459054
>I looked into linear pots, but can't justify spending $90-$400

Bourns linear... cost $1.60ea

https://www.youtube.com/watch?v=fQ19661UGx8

Stepper motors work by alternating a series of magnets in order to rotate its shaft by a certain angle. When the shaft is manually twisted, these magnets produce an electrical signal in a predictable pattern, which as shown in the video below, can be used as an encoder with the help of an Arduino Uno.

https://blog.arduino.cc/2018/07/16/stepper-motor-utilized-as-a-rotary-encoder-with-arduino/

>>1459042
>used hall effect sensors with a magnetized iron ball
[citation needed]
else fake story

why are variable capacitors such an obscure, expensive oddity while pots are commonplace?

>>1459075
learn 3 google

https://patentimages.storage.googleapis.com/e8/92/50/7f9394f84faa9b/US5583541.pdf

>>1459078
Variable capacitors are inherently more expensive to make, so any circuit where varying either R or C would work will use a variable resistor. That makes variable resistors more common than variable capacitors, which makes them cheaper still due to economies of scale. To the point where at audio frequencies it's probably cheaper to use a pot and a DSP chip than any circuit involving a variable capacitor.

>>1459063
Note that this only works with permanent magnet stepper motors, not variable-reluctance types. Also, some PM stepper motors may require non-trivial torque to rotate.

>>1459080
That's not an old mouse, that's a patent, a registered claim. Was such a construct ever manufactured? oldmouse.com doesn't mention it.

Why is leaving long legs on components like resistors and caps a problem?
The only argument i hear is they pick up inteference but it's not like i'm making radios

>>1459063
y tho, when you can get a detent-less rotary encoder with much better resolution?
did you make a wrong turn on your way to hackaday?

Is there something GNURadio can do that gqrx can't? I know GNU Radio is advertised as a sdr, but it seems I can anything that gqrx can

>>1459327
gqrx is a receiver application that provides a neat GUI for receiving a few different kinds of signals. gqrx was created with the GNU Radio toolkit. if you're doing something more specialized than gqrx is built to handle, you can use the GNU Radio toolkit/libraries to build your own signal processor, e.g. scanners, loggers, key recoverers, data demodulators, remote control receivers, any sort of transmitters

https://www.youtube.com/watch?v=14iBBIMpQ2Q
this guy used schmitt triggers to make a basic synth.
Does anyone have an idea what he's doing around 1:00 to make the arpeggio sound/make that bouncing noise? I assume something with two oscillators playing with each other, but how?

What's the standard method for high speed (MHz) logic level shifting?

>>1459415
an appropriate translator gate
there are wider devices as well, usually designed along the lines of the usual 74xx octal bus transceivers ('245, '373, etc.)

where would I look to learn how to design and build power supplies for my various projects? I pretty much just "turn up the power on my power supply until it works" and then add battery packs to match that power and I don't think that's very good in the long run

>>1459432
1. choose semiconductor manufacturers
2. explore web-based parametric selection guides
3. read datasheets
4. goto 1
>turn up the power on my power supply until it works
you don't specify your supply voltage in the early design phases? shiggy

>>1459436
my design is "put shit on the breadboard and see if it works"

>>1459211
>long legs on components
sometimes you just want to bend them over and stick it in.

>>1459441
she was asking for it

is there any utility to switch from through hole to SMT for prototyping past the breadboard stage?

>>1459444
>180 ohms
only token resistance, to be sure

>>1459440
try to learn to design to a spec. there's a bit more to an efficient power supply than guess-and-check
the TPS61040 datasheet is actually good reading for the neophyte boost converter user
orrr, just get one of those adorable little 2-for-a-burgerbux boost or buck modules and leave design for when you're designing

>>1459450
yeah nah, you redesign your board, not least because you'll stand to save a lot of money on square inches

>>1459453
what if I told you I don't know my knowledge level is at the point where I don't know what a buck or boost converter is

that's what I mean, I need a from-the-ground-up introductory course or book on small circuit power supply design

>>1459454
>I don't know
ignore that I forgot to delete it

>>1459454
Just tunnel through wikipedia, picking up knowledge and clicking on every link you haven't heard of. That's what I do, plus a little help from uni physics papers. Start with inductors, transformers, capacitors, diodes, MOSFETs, and BJTs, and work your way up from there to circuits. Comparators and op-amps and pull-ups will come in handy also.

In one of my previous jobs where I worked on a project involving an ADC for the first time, I was told that we should keep the signal away from the rails to stay in the linear region. Is the nonlinearity really that significant when the signal is close to the ADC's rails?

>>1459547
https://youtu.be/MJYy3yt8O1g
To be honest I couldn't watch through it all.

>>1459550
I also don't want to watch through it all. Do you have an in a nutshell answer?

>>1459551
I didn't watch it either. Look at an ADC datasheet and see if it has nonlinearity specs. As far as I know it has a slightly S shaped curve of digital values corresponding to analogue values.

I posted this on /wsr/ but no one responded
I need help with finding the thevenin resistance. Pic related is the answer but I don't understand it. Why is the 6k resistor in parallel with the 3k resistor? Why is the 3k resistor not parallel with 2k?

>>1459565
Where does the 2k resistor go?

>>1459569
What do you mean? The circuit on the left isn't connected to anything else if that's what you're wondering

>>1459570
then ignore it, lest it's a power supply and you're asked to do thevenin stuff

>>1459454
it's really only worth a chapter or two
maybe one of the basics books in the OP would get you to the point where you understand how power supplies are put together
in the meantime, consider buying a dozen or so of these
https://www.aliexpress.com/item/benis-converter-XDD/32885025475.html
they can be adjusted to any output voltage lower than the input. as a general rule you would choose a minimum input voltage at least 1-2V above the desired output voltage (stack up enough batteries or w/e)
if you need to raise the input voltage you would use a boost converter. these are less efficient than buck converters therefore not preferred.

>>1459547
at a guess, op-amps are definitely not universally equipped with rail-to-rail inputs and outputs. those that have RR inputs tend to have a region near one rail where they use different input devices from the rest of the input range

>>1459565
the resistance of the ideal voltage source is 0. replace it with a short for this part of the analysis. now you have a resistance that is 2k + (6k||3k)
the voltage of your answer is wrong tho. wanna try recalculating?

>>1456741
Just learn how to.strip it.properly.
There is a kind that you just have to heat and the solder flux eats it up.

>>1459415
>>1459419
In addition to chips specifically meant for level translation, there are also logic families with convenient input or output characteristics.
For example, basic 5V 74HCT stuff can be driven from 3.3V logic and 3.3V 74LVX can take 5V logic as input.

Where are you, /csg/ rudder pedal anon?

>>1459547
There are thousands of different ADCs, with different inputs. Some work just fine with R-R input and are specified for it, while some else don't. In particular, ADCs with integrated preamplifiers can have that nonlinearity problem. And like the other anon said, the opamp driving your ADC can be a problem too. Even amplifiers specified for R-R operation aren't totally free of non-linearities near their rails, but whether you see it or not depends on the resolution of your ADC. Conversely, if your ADC has high enough resolution, pretty much everything is non-linear in one way or another.

>>1459299
sorry anon your mom was distracting me
that thing she does with her tongue.
how many rotary encoders can you get out of old computers for free, in one day?

anon is trying to make cheap pedals for the rudder on his rocketship. this is diy not buy.
anon doesn't have nasa budget, and he needs to get to mars asap

>>1459613
A stepper motor (or quadrature encoder, as found in ball mice) only provides a relative output, so you'd need to recalibrate the centre position whenever it's powered up.

A pot (or a proper shaft encoder) provides an absolute output, so you'd only need to calibrate once.

Is 1A charging too much for this battery?
It says 5A but that sounds like way too much.

https://www.ebay.com/itm/3-7V-1500mAh-Lipo-li-Polymer-ion-Battery-for-cell-phone-Camera-GPS-PAD-504050/111861099475?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

Would there be any problems using that battery with this board? Is is safe to rely on the batteries built in over discharge protection?

https://www.ebay.com/itm/5V-1A-1S-3-7V-Li-ion-18650-Lithium-Lipo-Battery-Charging-Module-Charger-Board/322366742192?hash=item4b0e8e1eb0:g:xooAAOSwUchaNIn8