questions that don't deserve their own thread

[Anonymous No.685274]

qtddtot
Couldn't find one in the catalog.
Here's mine: What type of bulb is this, and are there shorter variants of it? I need to replace the one that was in my flashlight, and the one that was in it bumps against the lense. Bought from a pawn shop, so no owner's manual or parts list, and I really don't think this was the original bulb.

[Anonymous No.685295]

mini mag bulb 'ill work

[Anonymous No.685296]

>>685295
Thanks! Upon testing, I've also gotten a blue LED to work (only one I had laying around), but the hole into the reflective bowl is too small to fit it. Could just dremel that though.

[Anonymous No.685380]

>>685274
Look in the end cap for a replacement spare bulb in a plastic holder. It would be behind the spring, i.e. Maglite, item No. 4 is bulb.

[Anonymous No.685384]

What's this, /diy/?
Its about 20cm x 20cm, weighs around 7 kilos and is one solid piece of metal. I figured it was some kind of working surface, but no idea what it might be called.

[Anonymous No.685385]

>>685384

[Anonymous No.685424]

>>685385
That is a surface plate. Its use is to provide a precision surface for measuring on, for machining operations where you are working to tolerances of thousandths of an inch. http://en.wikipedia.org/wiki/Surface_plate

[Anonymous No.685446]

>>685424
>http://en.wikipedia.org/wiki/Surface_plate
Holy shit, that's the exact thing.
Thanks, anon.

[Anonymous No.685456]

I would like to make an etherkiller but don't know how to wire it. I'm using a UK plug and have the cat 6 cable.Which wire should go into the corresponding pins of the RJ45 plug?

http://www.fiftythree.org/etherkiller/

[Anonymous No.685464]

/g/'s /cyb/ thread has a pastebin full of useful links (re: meshnet info pages, programming guides etc) and I wanted to make one for /diy/

/r/ing any websites people have found useful, that others may not be aware of

[Anonymous No.685469]

>>685464

http://www.afrotechmods.com/tutorials/

[Anonymous No.685474]

>>685464

>what is the sticky

[Anonymous No.685499]

What's the most effective way to remove food stains and burn marks from formica countertops and spill stains from linoleum floors?

[Anonymous No.685524]

>>685499

pine sol

or a 2:1 mix of ammonia + bleach

[Anonymous No.685546]

>>685524

>ammonia + bleach

>mfw

[Anonymous No.685594]

what was that board that was stock marketie that we were all talking about all the time like 4 months ago. I havent been on it in a while and I forgot the url.

[Anonymous No.685595]

>>685274
That's one big penicl.

[Anonymous No.685828]

>>685499
burn marks, try ajax and a scouring pad or a scraper (razor blade OK). if it doesnt come out, it means the top layer has burnt and nothing can be done to restore it to original

[Anonymous No.685962]

Ok I broke the handle at the spot in pic related. Nothing's missing, the pieces interlock. How would I stabilize it? I tried superglue but it didn't work. They're some sort of plastic.

[Anonymous No.686013]

>>685962
hose repair clamp

[Anonymous No.686014]

Hey, /diy/, aside from refrigerators and air conditioners, what common appliances contain air compressors? I'm building a vacuum chamber and am trying to make it on the cheap by salvaging the compressor (which will be turned into a vacuum pump) from junk I can find free/cheap.

[Stihl No.686034]

>>685962
New handles aren't that expensive and a lot safer, but buy one. they're probably in stock at your local tool rental shop. What model do you have? I might be able to help ya out.

[Anonymous No.686040]

How do I blink an LED at a high speed?

I want to make a proximity sensor (not scalar just detection) I have an infrared LED and an infrared sensor (pic related) the problem is the sensor can only detect it when the intensity is changing, when the LED remains on and stable it detects nothing.

A 555 would be an option but with 9V I would have to step it down two times, one for the sensor and another for the LED.

Using attinys would be easy but the electronics spirit would be lost.

A joule thief would be too fast?

The frequency needs to be around 36kHz because it's the one remotes have and it should be optimized to detect at that frequency.

[Anonymous No.686049]

>>686040
Have you looked at small rc speed controllers ? If you get a servo tester you can vary the pulse width as needed

[Anonymous No.686065]

>>686049

A servo tester is basically the same as a 555 pwm controller.

I don't understand what you mean about rc speed controllers.

Thanks for replying

[Anonymous No.686095]

>>686065
RC speed controllers accept a servo input and use that to PWM your motor. In essence, it converts from RC-PWM, as a servo tester outputs, to actual PWM.

[Anonymous No.686102]

>>686095
>>686065

what that non said

You set the pulse width or how often the input voltage is turned on and off via the servo tester.

The speed controller send out the input voltage in pulses, this means you can control the motor speed in the same way as changing the voltage but since the motor sees the full input voltage you do not lose torque.

If you put the voltage your led requires into the speed controller and adjust the speed of the pulse you will change the flashing speed of the led, this is how you dim leds, You just switch it on and off so fast people can not see it.

[Anonymous No.686112]

>>686040
> A 555 would be an option

it's the BEST option, particularly as you can use the astable formula to generate close to 38kHz without needing a frequency counter.

> with 9V I would have to step it down two times

nope, to drive the LED, you just use a series resistor, which you have to do at any voltage anyway. for 20mAs calculate its value as (9 - 1.5) / 0.02

> the servo dudes

seem to be missing the point that OP has no need to adjust duty cycle for any reason.

[Anonymous No.686294]

>>686112

555s need quite a lot of power, I'll have to buy rechargeable 9v batteries because I'm tosing them by pairs, I also have several 3.7 li-po batteries I would lole to use. I like to find new and more adequate circuits rather than to use the easiest option. I wondered if there was a way to make a multivibrator circuit or something like to blink it at 39kHz.

Anyway I'll give it a try, I wanted to do a 555 pwm device, I've already made an 8-bit sinth and a transistor tester.

Thanks for your time.

[Anonymous No.686334]

> 555s need quite a lot of power

the old ones use something like 5mA but the more common CMOS ones are around 100uA which is negligible when compared with the load current. also if you connect the LED between pin3 and Vcc, then you can easily choose the ratio of R1 to R2 to give you, say, 10% duty cycle, which will decrease load current significantly.

[Anonymous No.686414]

>>686112

I'm going to make the circuit on the left, but using a 2222.

[Anonymous No.686496]

>>685456
I don't think it makes much of a difference

[Anonymous No.686511]

>>685380
>Look in the end cap for a replacement spare bulb in a plastic holder. It would be behind the spring, i.e. Maglite, item No. 4 is bulb.
warning!
if you change halogen bulbs you must clean them off with alcohol & clean paper towel after installing them. the salt from your skin will oxidize on the bulb and reflect heat back in, quickly burning out the bulb.

a lot of high-intensity light bulbs are like that: the oily residue from your filthy mitts will ruin them:::::::: you should wear new/clean rubber gloves to change them, and after you put them in, the last thing to do is you wipe the bulb glass off with a clean paper towel and alcohol

[Necromancer No.686768]

>>685274

I'm in the UK. I plan on making a table for playing tabletop role-playing games (D&D, basically). What wood should I use in what thickness and where can I get it for cheap? B&Q are pricey as fuck.

[Anonymous No.687058]

>>686334
>the old ones use something like 5mA
Only when idle.

During switching output, there's a small duration the transistors inside shorted itself.
Both the transistor at the last output stage turn ON making VCC flow from first transistor (Q22), to next transistor(Q24) and to GND.

That's why it's not weird if your 555 timer turn hot while in use.
You won't get that heat at only 5mA.

[Anonymous No.687059]

>>686768

Plywood is flat, thin, light and it don't gives problems when painted, to make sure you can sand it a bit with 240 grit before you paint. May look a bit cheapy though.

I don't see the point on using a thicker wood boards that aren't plywood unless you want to carve details in it having the right tools to do so.

[Necromancer No.687598]

>>687059

Cool, thanks, I'll have a look. I will embellish it somewhat with real wood.

[Anonymous No.687606]

>>687059
On this subject...

I'm trying to build a coffee table but all the plywood that I'm finding at Home Depot is warped to an obvious degree, is there anything I can do about this?

[Anonymous No.687616]

>>687606
Yes. Don't buy wood from big box stores. Get it from a lumber yard. You'll be wanting furniture grade lumber at that. I've only seen big box places like Home Depot an Lowes carry construction grade stuff, at least in my area.

[Anonymous No.688397]

I need to shorten some pant legs, I'd prefer to do this in a non-destructive manner. It's a thin poly/cotton blend if that maters.

[Anonymous No.688459]

Is there any way to shrink a shirt a small amount more, besides washing and drying on hot?

It's normal t-shirts. 100% cotton I think. I would like them to shrink just a little bit more to fit more properly. I've washed them in hot and dried hot a bunch of times, and that's not doing it.

[Anonymous No.688520]

What would be a quick way to improve the divide at the door in pic related? I'm moving out soon, but I wanna put something nicer than that plastic curtain. Some beads or some shit like that?

[Anonymous No.688568]

I'm going to an electronics store today (I live in a town and I have to go to the city to do so) amongst other components I want to buy an OP amp, is there any that is quite general to make some easy projects with?

The projects would be things like a microphone/piezo amplifier.

LM386?

[Anonymous No.688574]

What's the actual, technical name of a fitting with a ring swiveling through a ball, /diy/? You know, the one used for both door knockers, drawer knobs and fetish collars.

[Anonymous No.688575]

>>688568
dont. buy on internet.
but really I would suggest getting packs of an entire series of 5% resistors.

flux, solder. what tools do you already have?

[Anonymous No.688588]

>>688575

I wasn't asking about an entire set of things to buy, I already made a list, what I was asking was if there's are general OP amps to get started with and build small amplifier.

I already have plenty of other components and a basic knowledge about electronics, I just want to buy some others that I dont have but I need. Also OP amps to get started with them.

[Anonymous No.688639]

>>688588

Meh, I bought a single lm386, but plenty of other stuff.

[Anonymous No.688662]

>>688568
lm386 is pretty shitty for audio. You can spend the same amount of money on 10 much better op amp chips online as a pair of 386s at radioshack.

[Anonymous No.688666]

what's the cheapest material to soundproof my room from external noises?

[Anonymous No.688705]

>>688662

Ok, I don't usually buy online, but I'll probably get a credit card made just to do so.

>inb4 2014

Also I bought this pretty voltage meter to use it in a homemade power supply. It might sound very stupid but I always worked with digital voltmeters and I wondered if it doesn't needs any additional components? I already tried to test it with a 9v battery and it's quite accurate (+-0.1 volts).

[Anonymous No.688709]

>>688705

Crap, I forgot the picture.

Also /r/ing a circuit which can detect when the current is overpassing 1amp, I want to put a red LED in the meter to alert me if there could be any shorts.

The circuit can't create any noise nor peaks due to inductive parts.

[Quadrasaurus Rek'd No.688723]

>>688709
a 1A fuze in series with your load. if the fuze blows, you surpassed 1A :)

[Anonymous No.688727]

>>688723

But I don't want to be changing fuses constantly every time I make a short, the LM17 should be able to withstand shorts during short periods of time, thats why I would like a red LED to light up when I get close to 1,5 amps.

Maybe I could make a loop around a sensitive hall effect sensor and maybe add transistor to give it more sensitivity, but I don't like the idea of having loops around.

Also, how do I protect the circuit from self inductance peaks, like the one from a motor? I've seen in this cases a diode is placed from negative to positive, do the voltage ratings of the diode matter? Or I should just use a 4007?

Sorry for invading the thread with my questions but electronics has many things that I still haven't learnt.

[Anonymous No.688728]

>>685274
anyone recommend a shop in the uk for cheap plastic sheeting? I'm making a slip and slide tommorow, seems like you can buy it for a few bob in the us?

[Anonymous No.688745]

As someone who's never messed with circuits before, how long should it take before I can make a voltage-controlled oscillator for music? I'm planning on buying a breadboard today and I have a couple books on electronics on hold at the library, but because I've never done anything like this I have no idea what to expect.

Also, would it be easy to change the range that the oscillator would output at? Like, instead of putting out a range of 20-500Hz, being able to set it to put out something from 20-1000Hz, or even changing where it starts and ends (like, from 50-100Hz to 100-200Hz). Knowing nothing this all seems very complicated. Thanks in advance for your answers and patience.

[Anonymous No.688760]

>>688745

As I posted in another thread I did this, is a 555 8bit piano, it's a very simple circuit, you can tune it and play some songs with it.

The 555 is a very interesting chip, depending on the resistance in determined pins you can get a frequency on another, what means that you can change the frequency at your own will with just a couple of resistors and a 100k pot.

It outputs a square wave so it must be watered down with some capacitors and the sound quality is still far from professional synths.

Another option are microcontrollers, they are programmable, so instead of electronics you can learn programming languages and by following some tutorials and downloading some libraries you can have a nice quality 8-bit sinth or mini electronic piano.

I'm the guy who is flooding this thread with questions about electronics, I'm still a freshman and I make circuits to learn, and not the other way around, If I had to build a circuit just from the theory I couldn't even blink an LED, its faster to learn on the go.

Here's the link if you want to build one.


http://www.instructables.com/id/555-Pocket-SynthKeyboard/

[Anonymous No.688770]

>>688760
Wow, that looks awesome. I'll probably make that. Thanks for the link and your picture.

[Anonymous No.688771]

>>688770

Here's a pic of the back if you want to replicate the body.

[Anonymous No.689109]

What's the cheapest way I could make an outdoor workspace building/shed type thing that can hold enough heat to keep a person's hands from going numb in the winter?

[Anonymous No.689113]

>>689109
Stick frame, wrap it in tarps, have a propane or kerosene heater inside of tarp wrapped stick frame.

[Anonymous No.689155]

Is there a specific name for this part of wooden furniture? The sort of curved decorative framing on the edges of it?

I want to buy some to put around the edge of some furniture I have, but I don't know what to search for.

[Anonymous No.689160]

>>689155
Found the answer to this; they're called "Architraves". Thanks any way, /diy/nosaurs.

[Anonymous No.689186]

>>689160
architrave is more general, like skirting board when it runs up around a door is architrave technically.
If its just furniture or whatever they are just called timber mouldings

[Anonymous No.689200]

>>689155
"crown moulding" ?

[Anonymous No.689208]

>>689200
"Crown moulding" usually means plaster (as plaster is "moulded"), It was always called architrave when I was fitting kitchens with my father.

[Anonymous No.689247]

Hey I'm studying electricity myself not at a college or anything so my book doesn't have a solution page but one of the questions asks what kind of resistor and power rating is needed to drop a 250v 50a Generator to 40a output, I calculated I needed 2500w power rated resistor that is 25 ohm? Correct me if I'm wrong please? tl:dr need to kill 10a at 250v what kind of resistor do I need?
In return a gorgeous middle eastern woman.

[Anonymous No.689248]

>>689247
Can you post exactly what was asked in the book?

[Anonymous No.689252]

>>689248
Yup thanks attached.

[Anonymous No.689369]

>>689252
I don't know if the book expects you to just calculate with the motor as if it was a resistance, or what... but if it does...
First calculate the resistance of the motor using ohm's law.
Now calculate the circuit resistance needed to get 40A instead of 50A.
Subtract the motor resistance from that value. You are left with the current limiting resistor's value. Use ohm's law again to get the voltage across the current limiting resistor, now that you know it's 40A across your calculate resistor value.
From there calculate power.

[Anonymous No.689405]

>>689252
Normally I don't do homework, but right now I feel sufficiently lubricated by ethanol, so...

V=IR, 250V=Resistance of motor * 50A
Rmotor= 5 Ohm
250/40=6.25
Your resistor value =1.25 Ohm
Power is 40^2 A*1.25Ohm=2000W

That seems high, but this is a textbook, and I seem drunk. Also, a large portion of the grid resistors at work are rated 40A continuous, so who am I to judge.

Pic somewhat related, it's a 30A fuse that didn't pass 200% tests. 40A rated grid resistors were used to reduce current to required amounts.

[Anonymous No.689409]

>>689252

The correct answer is to walk out on whoever is seriously suggesting slowing a 12.5Kw motor by putting a resistor on it.

[Anonymous No.689411]

>>689409
>>689405 here
I agree completely with this, we burn out 225W resistors all the time at a decent cost to the company while trying to pull down amperage. The best answer is to tell those assholes to get a better solution to whatever they are trying to turn. A VFD would probably be better for this. Hell, a couple of guys on a chain drive would probably be a better solution for this, as long as you don't have to pay them some sort of minimum wage.

Ok... maybe I'm lying about that last bit.

[Anonymous No.689417]

So in the market for a house at the moment.

These little wooden strips over the plasterboard/drywall I assume are to cover up the seams?

A lot of the houses in the areas we're looking were built at a time where this was common.

Is it as simple as prying them off and plastering over the seams or would the whole wall need to be redone?

[Anonymous No.689427]

>>686014
air de-humidifiers. The cheap ones operate by cooling a set of finns and let the air pass over it, allowing the finns to pick up any moisture in the air.

These are normally fairly cheap to buy just for scavenging

[Anonymous No.689429]

>>688666
This varies with the frequencies you want to isolate.
Plaster plates is a common way to soundproof something El Cheapo. If you're not worried about the looks, get shitload of cardboard egg-trays and stick them on the wall somehow as they are good at redirecting the soundwaves so that the don't travel as easily through the wall.

[Anonymous No.689438]

>>689417
The walls are probably wood paneling under that paint. The cheap shit kind. So just plastering over it probably wont be an option.

[Anonymous No.689440]

What are the wires on this speaker for? I'd assume that the black is ground but since it's just one speaker, why are there three wires?
It's from a Grundig RR 276 radio.

[Anonymous No.689446]

>>689440
Same reason a single light bulb still has two wires going into it. Power in and power out. Speakers are DC so one side is your positive and the other is your negative. Without a complete circuit you're speakers wouldn't make any sound at all.

[Anonymous No.689449]

>>689438

Ah yeah true...

I could still pry it off and putty the gaps though right?

It's just ugly as fuck and so many houses are from that era :(

[Anonymous No.689455]

>>689449
Nope. Wood paneling expands and contracts with heat and moisture much more than drywall does. If you put spackle up in there it will start cracking in a season or two. Either live with it or get it replaced.

[Anonymous No.689459]

>>689446
>>689440
Black is case/safety ground, the other two are signal and signal ground.

Having different grounds for case and signal is quite common: USB, for instance, does it.

[Anonymous No.689468]

>>689455

Fuck my life...

I guess I'll just try to avoid getting a place with that bullshit on the walls or just plasterboard it.

[Anonymous No.689848]

Sorry for the stupid questions. This post is going to be pretty embarrassing.

After lurking this board for awhile I decided to buy a breadboard and some things to get started with. I have a large amount of resistors, a few assorted caps, and other basic things, including a couple LEDs labeled 2.6V max for "forward voltage" and a battery connector for 4 AAA batters.
AAA is 1.5V each, so that means the supply will put out 6V, right? So if the lights take 2.6V max that means I want a resistor between them and the battery supply...? I don't want to blow up my LEDs because I only have a couple. Any help would be appreciated.

[Anonymous No.689859]

>>689848
Yes you do.

Diodes (like most semiconductors) don't present a resistive load. They'll try to drop their forward voltage regardless of the resistance of the rest of the circuit. Effectively (this is a simplification), when you put them in a voltage divider, they take their forward voltage, and the rest of the voltage divider takes the rest.

If you hook a 2.3v diode straight to a 6v battery, the only thing limiting the current will be the internal resistance of the battery, and the resistance of the wires. The current flow will be 6V/Ri, where Ri is the internal resistance of the battery. I'd guess that'd be around 0.5 ohms, for a current of 12 amps, at least until something lets the magic smoke out.

What you need to do is find out a safe current for your LED, (say 0.5a), then imagine it in a voltage divider where that current is flowing. A 6V aaa battery, for instance, could have an internal resistance of 0.5ohms. We need a current of 0.5amps, so we need 6/0.5=12 ohms of resistance in our circuit. The battery adds half an ohm, so take that off. That leaves 11.5 for the divider. The LED is taking 2.3 volts of it, so the resistor gets 3.7 volts of it. So for 0.5A, the resistor needs to be (3.7/6)*11.5=7 ohms.

Note that 0.5A is quite an unreasonable amount of current for an LED to tolerate; less than 0.05 would be more realistic.

[Anonymous No.689861]

>>689859
You're a lifesaver. Thanks for the explanation, I'll try things out now.

[Anonymous No.689869]

I need to cut about 6" thick roots from a tree trunk where space is also limited (a fence is blocking one side of the trunk)? My search has narrowed down my choices down to a reciprocating saw, is this fine for the job? Or is there something better?

Thank you in advance.

[Anonymous No.689870]

I need to cut about 6" thick roots from a tree trunk where space is also limited (a fence is blocking one side of the trunk). My search has narrowed down my choices down to a reciprocating saw, is this fine for the job? Or is there something better I should use?

Thank you in advance.

[Anonymous No.690182]

>>689870
it will work fine, buy heavy duty 12" wood cutting blades with lowe tpi.

[Anonymous No.690300]

How badly will an analog tv signal degrade OTA digital tv transmissions?

I'm a /retro/ fag and want to set up a system like pic related

[Anonymous No.690310]

> How badly will an analog tv signal degrade OTA digital tv transmissions?

could vary from quite badly to disastrously badly, depending on the quality of the transmitter. it also depends on the expectations of the viewers. for myself, being spoiled by HD, I'd rather slit my wrists than watch fuzzy SD TV being transmitted by an amateur transmitter.

[Anonymous No.690322]

>>690310
Well if I want HDTV I can hook up my modern tv. Different folks have different tastes. Could I minimize the interference if I had the incoming antenna in another room and used shielded cabling? My broadcaster has variable output so I can limit range from a few feet to the whole apartment.

[Anonymous No.690335]

>>690322
Why not just cable your TVs in?

That way there'd be no interference, because you wouldn't be transmitting anything.

[Anonymous No.690346]

Anyone know where I can get thick transparent bags that are watertight and won't pop open easily?

[Anonymous No.690360]

>>690346
Any pet store that sells fishies. They'll always have a surplus of transport bags and polystyrene boxes. If you ask nicely, they'll probably start throwing them at you for free just to save them going on the bin.

[Anonymous No.690373]

>>690360
I think i'll need something that can seal a little bit better. Its to put something preserved in formaldehyde in.

[Anonymous No.690375]

Where should I get a job? Im a teenager and I want to build savings.

[Anonymous No.690378]

Please help me I'm a bit retarded.

In terms of stress/strain, am I correct in thinking that the brown portion of the bar is only affected by Force B?

[Anonymous No.690382]

>>690375
Assuming you're an American and have no previous work experience or any real qualifications, the one that will hire you. Think fast food, retail, or any store. If there's a building, walk in and ask about a job.

[Anonymous No.690399]

>>690378
If your brown block is hanging in the air, off the gray block that hangs from the ceiling, that brown block would need to support its own weight. The grey, ceiling, and connections would need to support more weight as we move towards the ceiling surface. You might do better with words though, maybe describe the setup or your application.

[Anonymous No.690409]

>>690399
This is just a theoretical conceptual problem that's been irking me. I'm studying Mech Engineering at uni and entering the new year I cannot seem to remember for sure how exactly this works. Pardon if the non-application nature of the problem goes against the nature of the board, I'd rather not filter through shit-posting on /sci/.

Let the brown and grey be different sections of the same bar. This bar is attached to the rigid ceiling above it, and is otherwise hanging in the air. There is a downwards force applied at A, a downwards force applied at B, and weight is negligible. Let the cross sectional area across the entire bar be constant, and forces A and B be applied evenly across this area.

My understanding is that the grey section of the bar would feel stress that is equal to Forces A+B divided by the cross sectional area, and that the brown section of the bar would feel stress that is equal to Force B divided by the cross sectional area. Is this correct?

[Anonymous No.690411]

>>690382


I have pretty impressive credentials interning at an institution of art. Wish me luck anon, fingers crossed for $13/hr starting pay

[Ellie No.690413]

>>690346
>thick transparent bags that are watertight and won't pop open easily?
Can you clarify the size, reusability requirements, thickness requirements, and applications?

For product Packaging -> Uline.com
For thicker, ebay "Triple Waterproof Camera Mobile Phone Pouch Dry Bag"
For Bigger, spacebag.com
For Cheaper, Zip-loc makes large (5 gallon+) zip-loc bags.

If you want to DIY something specific you can get rolls of Vinyl and adhesive from TAP Plastics. I would have to think a bit to come up with a /diy/ a watertight closure on these. HTH.

[Anonymous No.690427]

>>690409
Brownacre will certainly feel pull B. There's no path to transmit force A through the bulk of Brownacre though. Greyacre will experience both forces. I'm only running around with half an EE degree, so you're in your own for the dimensional analysis portion of the exercise.

Find he path.

[Anonymous No.690430]

>>690335
I really don't want to run a few dozen feet of cabling

[Anonymous No.690435]

>>690427
Sounds good, thanks friend.

[Anonymous No.690438]

I got superglue all over my metallic flashlight. It doesn't look like it bonded to it. But it's stuck pretty firmly. I think just scratching it off would look very ugly. Any ideas on how to get it off? I think someone suggested nailpolish remover, but I'm not sure if that would be strong enough. Even if it was, I'm worried that it might mess with the coloring.

[Anonymous No.690440]

>>690438
>acetone
Any solvent will do, really. I've found acetone to really smash the shit out of plastics without damaging the plastics I use to apply it. Get a small can of it at the orange store, and a dollar store toothbrush. Scrub the shit out of it and you should be clean in no time.

Follow all regular safety procedures etc etc
no flames
be ventilated
test your surface in an inconspicuous area


I know maglights are acetone safe due to certain distasteful activities.

[Anonymous No.690447]

>>690430
I've only ever encountered radio miniature broadcasts. You have some commercially produced tiny TV broadcaster?

Even a shit cabling job would probably work better.

Plan on aiming/tuning all hose receiver antennas.

[Anonymous No.690450]

I dumpster-dived a HP printer/scaner, it can't print (jams everytime) but the rest works. Any intresting projects I can do with the lcd screen or scanner parts? Otherwise I'll just take it apart for components as I already have a printer/scanner (that I never use lol). It's a hp officejet 4622.

[Anonymous No.690456]

>>690438
formaldehyde it's the solvent for superglue. good luck finding some of that just lying around

[Anonymous No.690464]

>>688574
captured ball ring
>body jewelry

[Anonymous No.690481]

>>690456
acetone will also dissolve cyanoacrylate superglue. Nail polish usually has other shit in it. See if you can find some pure acetone polish remover or go to a hardware store and buy an unnecessarily big can from the paint department.

[Anonymous No.690483]

>>690440
>>690456
>>690481
Thanks guys.

[Anonymous No.691041]

>>688709
You can also do this, whenever the fuse blow3s and the load is still connected the led will be on telling you that the fuse has blwon if you want to know how~does this work look for how lighted wall switches work

look around for fuse blown led indicator circuit

[Anonymous No.691152]

https://www.youtube.com/watch?v=DZD8iVpZPKk
vid is only 30secs
what are these things called?
simply a fancy drywall?

[Anonymous No.691197]

>>691152

the thing in the clip is very light, shiny on the back, and it sticks to a suction cup, so likely it's painted plexiglass.

the thing in your pic has unusually clean cuts, and doesnt seem to need too many screws, so it's likely cement-board.

[Anonymous No.691221]

10 year old battery pack wasn't holding a charge at all, so I opened the sucker up. Found pic related; fuzzy batteries.

I went and bought a corded drill because I hate batteries.

Is there anything interesting I can do with the remaining drill and charger bits?

[Anonymous No.691227]

>>691152
>expensive laptop
>expensive camera
>cant afford to finish the drywall

[Anonymous No.691229]

>>691221

get an 18V 6A supply for a laptop from the thrift shop for about $3. run wire to drill. you now have a second corded drill.

[Anonymous No.691250]

>>691221
Drill powered roller skates
Though you need another cheap drill

[Anonymous No.691251]

>>691229
Depending on the drill motor they can easily pull up to 30 amps under load. Still, worse cause you are out 3 bux you spent on the laptop supply.

>>691221
Charger is probably worthless. You could try and sell them for a bux or two on CL.

[Anonymous No.691255]

>>691221
https://www.youtube.com/watch?v=gC3rB9f7DaU

[Anonymous No.691256]

>>691255
Thats real fuckin neato but I don't have a 28v drill or a functional battery.

[Anonymous No.691325]

1) If I have resin inlay in a wood project, and after the resin cures I want to sand the excess down until it's all flush with the wood surface... how stubborn is resin when it comes to sanding? Compared to, say, wood glue residue?

2) I know next to nothing about LEDs and general electronic knowledge. If I'm looking for a small switch to turn one LED on and off, what sort of specs am I looking for? I try Googling "LED switch" and it just gives me switches with LEDs inside them, not what I'm trying to do.

[Anonymous No.691403]

>what sort of specs am I looking for?

depends on what kind of LED you're talking about. a run-of-the-mill LED that's used as an indicator light will take around 20mA at 1.7V, which means pretty much any switch will work. if you're talking about tactical flashlights or house illumination, then you'd a switch that can handle an amp or three at low voltage, like 12V.

[Ellie No.691407]

>>691325
>I know next to nothing about LEDs and general electronic knowledge. If I'm looking for a small switch to turn one LED on and off, what sort of specs am I looking for? I try Googling "LED switch" and it just gives me switches with LEDs inside them, not what I'm trying to do.

A LED is not like a regular lightbulb. Instead of converting electricity to heat and heat to light, it uses a specially doped semiconductor junction to convert electricity directly to light with relatively little waste heat.

This means that they use very little electricity and practically any switch will work. It also means that they require a minimum voltage to work. If you have 3 Volts or more (i.e. 2 AA batteries) you'll probably be fine. They are also "polarity specific". This means that if you connect them in the circuit backwards they won't light.

One tricky thing about LEDs is that they will, if you let them, consume enough current to self destruct. Your job, as a parent, is to protect it from this self destructive behavior by limiting the power it can consume. This is done with a "current limiting resistor". If you can post your LED's Maximum Current and your power supply's voltage, we can help you pick a value for your current limiting resistor using Ohms Law.

>Resistance (ohms) = Supply Voltage (Volts) divided by Maximum Current (Amps)

Once you know your Supply voltage and maximum current, you can use any switch that meets those minimum requirements. 99.9% will for one LED. You'll want an "On/Off" switch, not a momentary switch.

Here's an example switch:
http://www.radioshack.com/product/index.jsp?productId=2062497&retainProdsInSession=1

You can get these a LOT cheaper by finding a local electronics shop, or ordering them in quantity. I only show you the Radio Shack part because they are ubiquitous here in the states.

[Ellie No.691414]

>>691407
>LEDs

... And now she remembers to attach the Pic.

Attached is from Forrest Mimms III's "Getting Started in Electronics", which Radio Shack also carries.

Note the correct math formula for the current limiting resistor is on there. :D

[Anonymous No.691542]

>>688520
Just leave it open, looks better than having some shitty sheets there.
Let the next person living there decide what to do with it.

[Anonymous No.691720]

my question: where could i get tubes like this or of different diameters (but still relatively small) for projects. ive looked for a while and didnt find anything

[Anonymous No.691722]

>>691720
or this

[Anonymous No.691728]

>>691720
>my question: where could i get tubes like this or of different diameters (but still relatively small) for projects. ive looked for a while and didnt find anything
in the USA, US Plastics (online) sells some pretty small tubing.
in particular some of the medical tubing is really small (smallest I found quickly looking was .5mm ID):
http://www.usplastic.com/catalog/item.aspx?itemid=84015&catid=634
you'd need to buy a whole roll tho. and the stuff they sell is often industrial/medical grade, so it isn't cheap.

There is two sizes of aquarium airline tubing though,,,,,,,, the normal size and a 'miniature' size, that anyplace that sells pet supplies usually carries. I'd check if that would work first, since it is cheap and easy to get.

[Anonymous No.691731]

>>691728
thank you

[Anonymous No.691732]

I built a device with an ATTINY85 that only has a button as an input, an action is made when the button is pressed.

But I want to save energy when the button isn't pressed for a long time and I've looked into sleep modes, there seem to be a lot of different ones.

Anybody got any link to a tutorial to set up a sleep mode on an attiny85 and quit from it after a button is pressed?

[Anonymous No.691734]

>>691728
mcmaster.com

[Anonymous No.691739]

>>691732
i found this (scroll down a bit)

[Anonymous No.691740]

>>691739
forgot link
http://www.re-innovation.co.uk/web12/index.php/en/blog-75/306-sleep-modes-on-attiny85

[Ellie No.691744]

>>691720
>small tubes

A few years ago Amazon bought this fantastic little company called Small Parts Inc. Amazon sells all of their kit now, but the Web UI isn't nearly as fun as their old catalogs.

Some nice person has archived a bunch of their old catalogs at
http://www.smallparts2.com/

I'm sure they'll have what you need, quite possibly with free shipping through prime.

[Anonymous No.691745]

>>691744
thanks

[Anonymous No.691751]

>>691740

I saw it earlier but I'll take another look, thanks.

[Anonymous No.691753]

Not sure if this is a DIY question (I doubt it) but there is probably no better board for me to find someone that can answer this.

In age of the sail shipbuilding how were the frames attached to the keel (just placed on the smooth surface or in cutouts) and how was the keelson attached to this whole thing? Was it just bolted all the way through with a 1 meter long bolt or something?

[Anonymous No.691760]

I'm studying electricity and has a question, in a series circuit the resistive components must match the voltage of the source power provider, why must it do that? And why when amps or current is going through those resistive forces does it stay constant right throughout the circuit I thought resistors burned off current as heat dissipated as Watts wouldn't this have an effect on the Amperage? I though amps were little packets of Electrons, don't they get burnt off due to the resistive qualities of a resistor? The main purpose of resistors are to act as a voltage divider and to also limit current? Cheers.

[Anonymous No.691761]

>>691753
http://www.navyandmarine.org/ondeck/1800shipconstruction.htm

"The heaviest and strongest timber in the ship was the keel. It formed he basis of the vessel and was it's backbone. The keel was put together with massive timbers in order to provide the greatest possible strength. The keel was placed on large blocks which raised it off of the shipyard bed timbers, which allowed access to all parts of the keel timber as it was being worked.

Other shipwrights were engaged in building the frames, sternpost and stem while the keel construction was being completed. When this work was finished, it was time to devote attention to the "framing platform." This was a device which was set at right angles to the keel, and using it's dimensions shipwrights maneuvered each frame into it's precise location and then fastened it securely with a floor frame. In the period before powered sawmills these frames were beveled by hand in order for the frame to receive the curved planking. This work was done with a brad axe, and adze and the process was called "dubbing." There were several kinds of broadaxes and adzes, made up for specific tasks, like the offset handles of the tools for right and left handed cuts, and broadaxe faces ground flat on one side, beveled on the opposite in order to cut a straight line, or the use of a straight edge adz, or a curved edge adz to accomplish either flat or curved cuts. After the advent of powered saws these bevels were sawn into the frames, and a light "dubbing" might be required for a more precise fit. This was the saving of a good deal of physical labor, and allowed the time for the production of a ship to be shortened significantly. However, the down side of this use of power saws, reduced the number of men who could use these "dubbing tools" skillfully.

When the frames, sternpost and stem were in place, the vessel was said to be "in frame." Now came the strengthening timbers.

[Anonymous No.691763]

>>691761
I skimmed it but it doesn't seem to delve in the fastening method of the said frames.

[Anonymous No.691766]

>>691763
>http://www.navyandmarine.org/ondeck/1800shipconstruction.htm
oh youre right
" To be of oak, chestnut, hackmatac and yellow pine, moulded 16 in. at the keel, 10 in. at bilge and 7 in. at the plank sheer. The floors and first futtucks sided 8 in., balance of frame 8 in. Frames fastened together with 3/4 in, bolts. Room space 24 in."

thats all i could find

[Anonymous No.691768]

>>691766

[Anonymous No.691769]

>>691766
Oh that's rather weird because the two wooden ships I saw being build used wooden nails to build a frame out of futtucks.

[Anonymous No.691770]

also

"On small craft the planking is fastened to the frames by using copper nails which are clenched over or riveted on the inside of the hull, drawing the two parts tightly together. On large ships with thick timbers, parts are joined using TREENAILS, pronounced trennels, which are round or octagonal pieces of oak driven into undersize holes in the planking, frames and other timbers."

http://my.fit.edu/~swood/History_pg3.html

[Anonymous No.691772]

>>691769
one of these has to be accurate, good luck

[Anonymous No.691774]

>>691770
Yeah yeah that's for the hull or deck planking and I assume the riveted one is clinker build but I am talking about the joining of keelson to keel and the frame sandwiched between it. It has to be one of the strongest connections otherwise the ship would fall apart.

[Anonymous No.691778]

>>691774
i found that earlier but i forgot the link hold on

[Anonymous No.691780]

>>691774
is this any more helpful?
http://njscuba.net/artifacts/obj_hull_wood.html

The illustration above shows most of the basic components of a wooden ship's frame. The keel is the backbone of the vessel. Attached transversely to the keel at regular intervals are angled assemblies known as "floors". The floors carry the vessel's ribs, shown below. The keelson is mounted atop the floors, sandwiching them into an extremely strong structure. The keelson provides additional strength and stiffness to the keel and floors. Below the keel, most vessels also have a "false keel" ( not shown. ) the false keel is generally not a load-bearing structure. Rather, its purpose is to protect the keel from wood-boring organisms and accidental groundings, and also to provide lateral resistance in the water so the ship will track straight in a crosswind.

[Anonymous No.691781]

>>691780
Well it's not telling me anything I didn't know yet, I just want to know what was used for

>The keelson is mounted atop the floors, sandwiching them into an extremely strong structure.

But I think I might need to find an actual ship builder to answer that.

[Anonymous No.691783]

>>691781
more like historian

[Anonymous No.692549]

>>686013

Thank you, this ended up working. Clamped it and wrapped it with black electrical tape.

[Anonymous No.693243]

Headphone repair question. I two pair of headphones that I want to use parts from one to fix the other. One pair has a broken headphone jack where you have to bend it in a million angles to get it to properly work. I took the headphone jack (1/4) from one pair and want to solder them to the wires of the other (3.5mm). Picture included what the wires are.

I am assuming that the black wire is an extra ground (I don't know for sure I am just guessing if someone knows for sure would be helpful) would this in theory work? I know there are converters that take it from 1/4 to 3.5mm, but I don't know if if I could strictly power a 1/4 with the wires from a 3.5.

Unfortunately the picture isn't the greatest, but the larger stripped wire is White|Black|Red|Blue, (1/4) the other wire is just White|Red|Blue (3.5)

[Anonymous No.693264]

What happened to this? It looks like an inductor and the core has melted, but I'm not really sure...

[Anonymous No.693340]

>>693264
it's a little piece of foam saturated with wax. Common practice so the coils don't vibrate, move, or loose their shape. It also keeps moisture out.

[Anonymous No.693350]

>>693243

put headphones on your head, insert plug into source of music, and touch wires at random until you get the right combination. takes 2 minutes to figure it out.

>but I don't know if if I could strictly power a 1/4 with the wires from a 3.5.

there's no electrical difference, just use the size you're most likely to use, 1/4" for musician types, 3.5mm for everyone else. if you have no preference, the 1/4" jacks are much more sturdy and reliable.

[Anonymous No.693390]

>>693340
Ah, that makes sense. Thanks Anon.

[Anonymous No.693589]

>>685962
Try Q-bond

[Google should be your friend No.693673]

How do I create a 7v voltage drop? I must drop the voltage from 19 to 12 volts, normal resistors would fry and the best idea I had are 10 silicon diodes in series.

[Anonymous No.693686]

>>693673

Uh, two high-power blue or white LEDs in series would work, assuming you don't need drive currents of more than a couple of amps.

[Google should be your friend No.693694]

>>693686

Max current is set at 2.1 so the LED's would fry instantly If I don't use a high power resistor.

[Google should be your friend No.693702]

>>693686

But I'm going to use around 20-100mA, but it will have a coil and a current peak could be higher.

[Anonymous No.693710]

>>693673
7V Zener diode, part chosen for the current you expect to be passing through it.

But a voltage regulator might be a better solution. Like an lm317 or similar.

It depends on what you're doing, how clean your input is, how clean you need your output, how sensitive your circuit is to slight voltage changes due to changes in load current... things like that.

[Google should be your friend No.693720]

>>693710

>Voltage regulator

For fucks sake, I have several 7812 laying around and I had not thought about them, although maybe they will heat too much, 78xx are quite inefficient, I'll take a look at the formulas...

Just looked at it, apparently the power dissipated is equal to the voltage drop per the current of the load: is 10mA for an LED and some more for a 12 volt relay (I don't know how many exactly), datasheet is sheit.

Even if I use 50 mA the power dissipated should be lower than half a watt.

[Anonymous No.693724]

>>693720
>78xx are quite inefficient,

True, but any non-switching solution you pick - resistor, diode, zeners, linear voltage reg - is going to be inefficient and waste power. Because have your load current (say it's 50mA) you're going to be dropping 7V one way or another, all will be inefficient, no way around it (practically speaking) except for a switching converter.

If you use an 7805 (or an LM317), yes those will get warm, but you can use a clip-on or slip-on heat sink.

[Anonymous No.693732]

>>693724
>7805
meant to say 7812

[Anonymous No.693749]

>>693724

Just measured the amps, 60mA is the result. The 7812 gives about 0.4 watts of heat, quite a bit, luckily it will be implemented in a security circuit which will be on some seconds on in case of something goes wrong and then turned off.

[Anonymous No.693935]

>>693673
You can use a LM7805 (78L05 up to 500mA if I remember), and put a potentiometer (or a couple of diodes) from pin #2 to ground.
It's a neat little trick that works great.

[Anonymous No.693962]

>>693935
it works, until something short circuits, then everything breaks. Normally the 7805 goes into a short circuit mode due to the crowbar circuit inside. This is done to protect external circuitry powered by the 7805. When you put those diodes there, they will experience a very large current in short circuit condition, breaking the diodes and thus sending something in the range of 10 volts to your circuitry.
NEVER do this trick if you are powering sensetive electronics.

[Anonymous No.693964]

>>693673
Use a bipolar transistor and zener diode.

[Anonymous No.694313]

>>693964

I already used a lm7812, case dismissed.

[Anonymous No.694324]

Stepper motor wires.

In order to be consistent and easy-to-follow, I would like to keep the coloring of the wires the same when connecting them to boards (there are multiple stepper motors). I got the colored wires for the solid colors, but for the life of me, I can't find a place that sells white wires with colored stripes.

Does /diy/ have a preferred place to buy electronic wires?

[Anonymous No.694719]

>>694324
I usually use wires from stuff i take apart. Wires and motors are two of the few things i do not buy.

[Anonymous No.694728]

>>694324
ethernet cable.

[Anonymous No.694734]

Planning to paint my garage door (metal) which hasnt been done since I've been alive. So over at least 20 years its horrible lime green has gone very faded

Cant be bothered to buy an undercoat, but do I need to if I was doing going to paint it white?

Also will the type of paint look OK if applied with a brush, or do I need a roller so I dont get stroke marks?

[Anonymous No.694738]

>>694734
is it a roller door or flat panel?
you need to chip and sand it or at least blast it with piss(high pressure hose)

[Anonymous No.694739]

>>694738

flat panel

yeah was planning on using a scraper and then coarse sandpaper before washing it

do they sell specifically "garage door paint" or is it external gloss or something?

[Anonymous No.694743]

>>694739
you will specifically need paint meant to adhere to metal. and whatever metal that is. so just identify the metal and tell the paint store you need paint to stick to that metal door. I would guess galvanised steel? I'm not sure if scraping galvanized steel would be a good idea as it might rust after

[Anonymous No.694745]

>>694743

OK I'll take a look in the store and ask someone if needs be, thanks

[Anonymous No.694746]

>>694743
although it might be easier and cheaper to just buy whole new bonded panels and scrap the existing panels on the door. I dont know. paint is stupidly expensive in australia.

[Anonymous No.694778]

Galvanised paint needs an etch primer for best adhesion. Clean it with scotchbrite and detergent, let it dry, then etch prime.

[Anonymous No.694780]

Galvanised metal, that is (dammit)

[Anonymous No.694884]

I'm the guy of the power supply again, I want to build an electronic fuse, so far the one I did with the PNP transistor works but it must be adjusted according to the voltage output. Maybe adding some capacitors so the PNP doesn't senses ground and another transistor it would be stable from 16 to 1.25 volts.

Any suggestions? The triac thing seems a good idea but I don't know which model of triac and transistor should I use.

Video related, it stops working that fine when I go under 12 volts.

[Anonymous No.694886]

>>694884

tfw you forget to attach it.

https://www.youtube.com/watch?v=1nVzUUYPm3w

[Anonymous No.694897]

>>686014
This is a little late, but perhaps you could just salvage the pump from an old vacuum cleaner? Don't know how much air you need to move but it might do the job

[Anonymous No.694912]

Is there an easy way to identify titanium grade? Between GR2 and GR5. Its a sheet roughly 5.5mm thick.

[Anonymous No.694919]

>>694884
Your circuit is comparing the scaled output voltage to the input voltage, when you (IIRC) wanted to sense the output voltage alone.
Use an NPN, emitter grounded. You don't need a TRIAC for DC, an ordinary low power SCR is fine and easier to drive.Component ratings depend on circuit details, but it is doable with a random low power SCR like 2N5062 and a low power transistor like BC547.
Don't forget to add some way to reset the circuit.

[Anonymous No.695068]

>>688728

what is your equivalent to Home Depot? general hardware store?
you can buy 100 feet of it for $15

[Anonymous No.695072]

>>690375

try to think of something that your interested in.
it might make the job more pleasant if its related to your interests.
do you like computers or electronics?
do you like music?
vidya games?

[Anonymous No.695285]

>>694897

Vacuum cleaners don't have a pump, they have a fan.

[Anonymous No.695481]

Is there supposed to be some sort of seal or o-ring or gasket or something right there?

This is the back cover of a Duo-fast stapler.

[Anonymous No.695658]

Because I'm a fucking idiot I want to put a diode on my phones somewhat hacked to shit usb cable, I have no idea what the thing would draw on its own, I'm guessing maybe 600mA, but chargers could pump out 1A and I have no fucking clue how much a phone would draw if you connected the pins backwards.
Anyway, I've read online that you need about 150% the Amp, well I found these
www.jaycar.com.au/productView.asp?ID=ZR1005, they're 400V but only 1 amp.
I know that's 400 watts but I have no clue if that really matters here, if amps is the killer.
Is this shitting it in or should I get something with more edgeroom? I mean, who knows, I might accidentally connect this thing up to a 12v power source by accident, maybe I should throw in a voltage regulator as well...

[Anonymous No.695667]

>>695658
Sure thing on VR. Best bet is to buy the dilithium filled diodes.

[Anonymous No.695670]

>>695667
Gotcha, thanks!

[Anonymous No.695792]

Guys how do I into hand sewing?

[Anonymous No.695833]

>>695792
Buy some yarn and knitting needles to start off.

[Anonymous No.695838]

Any ideas on how kill myself in interesting /diy/ ways?

[Ellie No.695856]

>>695838
>Any ideas on how kill myself in interesting /diy/ ways?

Build a Scuba rebreather, without the oxygen addition feature. The CO2 absorbent is made from Pickling Lime and Lye.

Don't do this unless you really want to die. With no CO2 to trigger your breathing reflex it's Breath breathe breathe bre-click. Dead.

[dungenMaster No.696279]

>>693673
Just use a 7812 voltage reg, 12v 1A but I'd heatsink it just to be safe

[Anonymous No.696369]

>want to buy sheets of 1/8in thick medium density fiberboard
>home depot sells it in 1/4in thick, don't have the equipment to cut it down to 1/8in thick
>google it with -home depot added to find other sellers
>fucking nothing shows up

Jesus christ

[Anonymous No.696372]

>>696369
Forgot my question, does anyone know of a retailer who will ship this shit, or of some large chain of stores that might be near here that cut and sell MDF that have the ability to cut it down to 1/8in thick

[Anonymous No.696381]

>>696369
>>696372
nevermind got it

http://woodnshop.net/medium-density-fiberboard/

[Anonymous No.696386]

What should I specify when buying a toroid to make a joule thief to power some UV leds with 2 AA batteries?

I know it should be as large as a penny but I don't know the codes for it having the correct inductance.

[Anonymous No.696551]

>What should I specify when buying a toroid to make a joule thief to power some UV leds with 2 AA batteries?

- it's not really about inductance, but more about the number of turns. for this design, for example, the guy wound 13 turns "just because". different number of turns will work just as well.

- it's much simpler to wind your own rather than trying to source a specific part

- you can find ferrite donuts in all kinds of dead electronics, for example the power supply in an old laser printer, or set-top cable box, or laptop supply.

[Anonymous No.696558]

>>696386
UV LEDs are 2-3v and two AAs in series is 3v, so I don't see why you need a voltage booster.

[Anonymous No.696584]

>>696558
2 AAs in series isn't 3v for very long.

[Anonymous No.696651]

>>696558

UV leds are around 3.6 I guess, also I'll be using NImh, that means I'll have a maximum voltage of 2.4 volts.

>>696584

This, also with a joule thief I can keep using the batteries until their minimum, if used 3 AAs they thing would stop working at 1-1.2 volts.

[Anonymous No.696653]

>>696551

I found several ones in computers and other places and they are not all the same. Some made the led shine very bright and other wery dim using the same current.

[Anonymous No.696798]

Outside of 8th grade shop class I have no experience with woodworking or access to power tools.

Would it be unfeasible for me to build a small woooden box with a hinged lid and dividers?

[Anonymous No.696957]

>>696798

Precision will be your main problem, with the right tools you could do one in five minutes, not too much experience would be required, just some exact calculations.

With just a hand saw is quite hard to get anything right, even if its off just by a millimeter or two, you'll have to sand quite a lot of times to get everything to fit tightly.

Making good measurements is crucial, the better you measure and mark the pieces the less time you'll spend sanding.

Get a mitre for 45 degree cuts, that'll help a lot when making the body of the box.

There are plenty of tutorials about making boxes.

[Anonymous No.696975]

>>688459
could be pre shrunk shirts, most do this method these days so idiots who cant wash clothes dont fuck it up.

[Anonymous No.697592]

>>689417
If you're not adversed to painting, that style could potentially look rad as fuck.

[Anonymous No.698242]

Is it worth it to use an old pc as a controller to drive 3d printer/cnc?
The idea of having dedicated machine with usual I/O such as keyboard/monitor is what attracts me, as well as the fact that I have them lying around.
Also you can hook your stepper drivers right into parallel port, right?

[Anonymous No.698575]

>>698242
>Is it worth it to use an old pc as a controller to drive 3d printer/cnc?

I have an HP running Windows 2000 for the proprietary CNC controller on my Spectralight Mill. If it ever dies I will replace it with a Linux box running EMC2.

For a 3d printer, I am much more likely to use a RAMPS compatible controller, as so many people are using them. I don't want to be the one finding the weird bugs that only occur on a different platform.

[Anonymous No.698625]

>>698242
1. I've seen people run CNC software using DOS, because you can get realtime low level control of the hardware without interruptions (inb4 you forgot int 0x1c). These days one might use freedos.
2. If the drivers take 5V logic input then yes.

[Anonymous No.698826]

>>698575
>>698625
Thanks guys.

Here is another question: lets say I have 2 parallel ports on my old pc, why is it bad idea to connect steppers through power transistors to those 2 ports?

[Anonymous No.698836]

>>698826

Issues with ground loops and fault protection.

If something goes wrong, you might fry your parport. Normally these kinds of things have optoisolators on them to protect the computer if such an event occurs.

[Anonymous No.698837]

>>698836
Those old pc's have no value so I won't loose much if I fry them.
If that's the only downside I guess I'll go for it, seems like interesting project.

[Anonymous No.699139]

I want to build the circuit in the figure, I've got all the components but I haven't found transformer so I've decided to build it myself.

I know 1k:8R is the resistance ratio of the coils, but how the heck do I know how many turns should I wind and the gauge of the wire?

I'll be using the transformer from a big CFL lightbulb, it has only two connections (a single wire) so I guess it's designed to produce voltage kicks like a coil would do, I just have to unwind it and wind it again with the proper copper wire length and gauge, right?

Also the guy at the shop probably didn't understand what 1k:8r meant, he showed me a huge ass transformer, maybe if I tell him it was a ratio and not the actual value he can find the good one.

I've seen the radioshack one but I haven't found any datasheets.

Thanks for your time.

[Anonymous No.699144]

>>699139
If you wind it with same gauge, it should be 8 turns primary and 1000 turns secondary (8:1000).
Now you need to know max current flowing through primary coil. Thickness of wire can be counted using expression d=0,714*sqrt(I) where I is primary current and d is diameter of wire.
Or you could just wire it 8 turns with 0.75mm wire and 1000 turns of thin wire and see what happens.

[Anonymous No.699154]

>>699144

Wow, thanks! I guess the intensity on the first coil should be around one or two amps since the transistor shorts the 12 (or 9 volt) supply to ground with the solely resistance of the path. Your equation tells me I should use 1mm wire, but I probably end up using like 0.75 mm or less because it's the one I have.

For the secondary I'll use a thin wire I have, I guess it's around .1 millimeters., that should do the job.

I wish I had a transformer winding machine with a counter.

[Anonymous No.699157]

>>699144

I'm going to wind the bigger one, should I wind the big wire first?
Same direction for both wires?

[Anonymous No.699161]

>>685594
/biz/?

[Anonymous No.699163]

>>699144

There's a gap in the ferrite loop, does this means something?

[Anonymous No.699181]

>>699144

>8 turns primary and 1000 turns secondary

I thought about it twice and I don't think it's going to be so simple.

1k:8R is a resistance ratio, not a winding ratio, If I used the same wires it would be ok but that's not the case, that said I proceeded to make some calculations to make my transformer.

The gauge affects the resistance, for example, 1.70 meters of 0.75mm wire gave 0.5 ohms, while the same length of 0.1 gave me 2 ohms.

I'm going to search for the formulas to see how many meters of each wire I need.

If I can't do this I'll go and buy one.

I also found a transformer without a gap, I guess it'll work better.

[Anonymous No.699189]

>>699181
>I thought about it twice and I don't think it's going to be so simple.
Yeah, it isn't. The turns ratio would be sqrt(8):sqrt(1000), or around 1:11, if you wanted 8:1000 ohms impedance ratio. The actual number of turns depends on your transformer core and the drive signal. Basically, you need to have enough inductance and the core must not saturate.
On the other hand, the transformer isn't too critical in that application.

>>699163
The gap lowers the effective permeability, which in turn increases the core's power handling capability. It also makes the inductance more predictable. The most obvious drawback is that you need more turns for the same inductance.

[Anonymous No.699193]

>>699189

I think I'll make a trip to the biggest electronics store I know to see if they have any.

[Anonymous No.699206]

I'll start here but some R/C fags might be able to help me a bit more.
I just tore apart my dead laptops battery and it's full of these nice li-ion cells, 4v each, the output on the battery terminals is 7v.
I was wondering what would be the best way to use them as a USB charger, and to charge the batteries themselves, without wrecking them to all fuck.
I'm not very good with the whole battery thing, but I'm learning.

[Anonymous No.699208]

I'm about to start a project to attach LEDs to a pre-made speaker to create a (very rudimentary) audio visualizer. I'm not sure, but I think that simply wiring the LEDs(And resistors) in parallel with the speaker should be enough, I'd just need to boost the volume if I wanted the light to be visible/sound to be audible since I'd be leeching power. Am I on the right track, or should there be some more to it? I just want the lights to flare simultaneously, I'm not looking for exacting visualization. Thanks for any help you folks can give.

[Anonymous No.699212]

>>699206
How stupid would it be for me to just wire a cell up to a housing for a 18650?
Both cells have the same voltage, they're both used in laptops, seems reasonable to me.

[Anonymous No.699213]

>>699212
Fuck it, seems like it'll work.
And ordered.

[Anonymous No.699214]

>>699193

Indeed, I winded all the wire I could but I ended up with a 13R:0.5R, I could hear it scream due the saturation, I touched the wires of the voltage multiplier and I got a small shock, but no sparks. Also the transistor was extremely hot.

[Anonymous No.699238]

>>699212
it will work but it wont fit. you can't fold the batteries as I discovered. you should order a usb ubec ubec and wire it up to the cells. dont even need to disassemble them. just put them back in the laptop battery case and wire the ubec to them. dont forget to do a 3v cutoff or battery warning thingo. also, those laptop batteries have a bms that does this. dont throw that away or fuck it, its actually useful.

[Anonymous No.699249]

>>699238
I have no intention on trying to fit it in the case, I was thinking more tactical arm band.

[Anonymous No.699279]

>>699249
there are stand alone boards on the bay of Es. I am considering building a charge control/ usb charging module and fitting it into ingress themed arm bands. my limit is finding reliable lifepo4 batteries. the smaller ones only come in round cells which is upsetting. otherwise I would use the 20Ah A123 batteries but they're almost the size of a sheet of A4.

[Anonymous No.699296]

>>699214

Rising the frequency of the 555 helps to overcome problems with saturation, in fact I've been able to get 2mm sparks out of that shitty homemade transformer, adding some resistance to avoid frying the transistor of course.

Note to myself: Buy 1watt resistors
Note to myself (2): Don't touch 1/4W resistors when under a big load.

[Anonymous No.699552]

Not sure if this is within /diy/'s forte, but I'm looking to cast aluminum (or some other cheap, strong-ish metal) to make pendants that have a bit of weight to them. I know there are several things to worry about here, but my main one is how to construct a proper mold. I read online about using clay, but that may not work as this particular object has lots of divets and fine details that might get fugged when I pull the object out of the mold. So how would I go about constructing a mold for a small, intricately detailed object that can withstand the temps. of molten metals?

[Anonymous No.699609]

>>699552
Google: Investment casting

You make a wax replica of what you want to cast, attach sprues (metal-filling holes) and risers (columns for extra metal so it doesn't shrink), and coat the whole thing in investment casting plaster. When it's dry, put it in an oven and melt out the wax. Then take the hot mold and pour the metal in. Let it cool and you can fetch your cast object out of the middle.

It works for gold, silver, aluminum, copper, etc.

Do you have a metal melting furnace yet?

[Anonymous No.699628]

>>699609
>Do you have a metal melting furnace yet?
No, but I imagined I'd need one.

[Anonymous No.699668]

Here a question I dont want to make a thread for.

My various alarms dont wake me because im a heavy sleeper and im going a bit deaf. They make alarms that vibrate your bed to wake you but I wanted to try and diy one.

My idea was to get a cheap alarm that just plays a tone and wire an audio jack in place of the speaker so I can run a cable to a transistor that operates a relay that controls the motor.

Will the signal that was supposed to go to the buzzer be strong enough to trip the transistor on?

[Anonymous No.699675]

>>699668
>Will the signal that was supposed to go to the buzzer be strong enough to trip the transistor on?

Might not be, get out a DMM and check the AC voltage when the alarm is on. Voltage depends on how loud you turned up the volume.

Your circuit could be something like this:
alarm speaker signal -> peak detector -> comparator -> transistor -> relay

[Anonymous No.699715]

In this circuit how would I put an indicator led at both switches.

I would assume at the red/blue wires with a resistor in front, but should it be put there in parallel or should I just do it in series?

[Anonymous No.699721]

>>699675

Got a reply for this. I got home and tested the speaker during alarm sounding with my DMM. Fluctuated between around 3 - 8v on DC mode and between 12 - 18v on AC. There is no volume, the speaker looks like a piezo buzzer.

I'm googling comparator and peak detector now because I'm still a novice.

[Anonymous No.699723]

>>699721

I tried this. I didn't expect it to work, and it didn't. What exactly am I not understanding? I tried putting the probe on both sides on the piezo and the led just lit up no matter what.

[Anonymous No.699733]

>>699723
>probe
You need ground connection too.

[Anonymous No.699781]

>>699723

probably wanna do something like this. the diode and capacitor form a kind of peak detector so your LED will go on cleanly, instead of flashing very fast.

[Anonymous No.699937]

>>699723

The connection for the base must be supplied by the same power source, that means, if you have a radio powered with 12 dc you cant add another power source and use both with a single transistor, I suggest you find the positive and negative terminals of your radio to attach them to the transistor, use a resistance to avoid overpowering the LED if the voltage is higher than 9v.

Also add a capacitor as >>699781 said to keep the LED on for more time between pulse and pulse, that will avoid molest flickering but may also reduce the sound quality.

[Anonymous No.699944]

>>689155
that is an ogee nose

[Anonymous No.699954]

I'm working with high voltages and low pressure and I'm afraid I'll be irradiating myself with x-rays.

How can I make a good and cheap sensor?
I found this but I doubt I can find Zinc Sulfide.

http://www.noah.org/science/x-ray/detector/

[Anonymous No.700112]

what's the proper name for threaded high tension couplers that connect two metal poled/round beams? has a slot in the middle to tighten it? looks kinda like pic related, sorry.

[Anonymous No.700119]

>>700112

Turnbuckle? Though those usually have hooks attached.

https://www.google.com/search?q=turnbuckle&espv=2&biw=1440&bih=815&source=lnms&tbm=isch&sa=X&ei=LRQdVPH_N6qLiwLH7ICgCg&sqi=2&ved=0CAcQ_AUoAg

A coupler nut is usually what you'd use to fasten threaded rods together, since a turnbuckle requires both a left-hand and right-hand thread.

https://www.google.com/search?q=coupler+nut&espv=2&biw=1440&bih=815&source=lnms&tbm=isch&sa=X&ei=UhQdVMuqOcmLiwLg14HwAg&ved=0CAcQ_AUoAg

[Anonymous No.700139]

Hi/diy/ho!

Can an electrician check pic related for me. My answer was I needed a 2.9ohm and 49.2w rated resistor to hook the light up, is this correct?

[Anonymous No.700144]

>>700139
>50 watt lamp
>49.2 watt resistor
Ha ha. Also, stupid homework question. Get a 24V bulb instead. Or use another 12V bulb as resistor.

[Anonymous No.700145]

>>700144

Ok settle down there horsey we all have to start somewhere, I mean a 100watt resistor and 3.24 ohms is that right?

[Anonymous No.700151]

>>700139

Wait...this looks familiar...did you post one a while back and have some guy point out the retardation of using a resistor to slow a multi-kW DC motor?

The answer is similar here:

Pimp-slap the guy suggesting you seriously use a 50W 2.88Ω resistor instead of just getting a properly-rated head lamp.

[Anonymous No.700152]

>>700145
This is /diy/, not /homework/.
The resistor and the lamp are in series, so the current through them is the same. They're both supposed to have the same voltage across them, too. Knowing that, no calculations are needed to deduce the resistor power dissipation.
100 watt resistor would be ok in a practical circuit, but that's not what your teacher is expecting.

[Anonymous No.700153]

>>700151
>>700151

[Anonymous No.700212]

can i plug a welder on a 5hp generator to weld outdoors ?

[Anonymous No.700217]

>>700212
What kind or welder?

[Anonymous No.700222]

>>700217
an old arc welder

[Anonymous No.700225]

>>700222
It will probably work for short periods of time, depending on how many amps you're pulling. You will probably have to make an adapter by getting the correct outlet for the welder and attaching it to the correct plug for the generator. I can weld for short periods of time with my AC buzz box hooked to my 5000 watt generator, so you're probably good.

[Anonymous No.700231]

>>700225
thanks bro

[Anonymous No.700235]

>>700139
>49.2w
I think you need to put the rounding down and take a breath.

[Anonymous No.700258]

Okay, so i'm a complete newbie when it comes to these things, but is there some technique/block/tool you can recommend to me for knife sharpening?

I have a few cheap sharpening tools at the moment, which keep the blades and kitchen knives i currently have 'moderately' sharp - but i want these things to be like fucking razors.
How do i go about that, if it is at all possible?

[Anonymous No.700301]

>>700258
Google 'scarey sharp'. it uses a flat surface and sandpaper.

[Anonymous No.700490]

I'm going to be buying a couple pounds of 500 mesh, 30 micron aluminum powder.

The problem is nobody is listing volume online that I can find, and everybody's closed today so I can't ask.

Do any of you have any idea how much volume something like this would have?

Thanks

[Anonymous No.700560]

>>700258
You really don't. What you want to be doing is learning to use a kitchen knife properly.

A kitchen knife is sharp enough when it can cleanly cut fiddly stuff like tomatoes, raspberries and grapes. Any sharper is stupid: you'll hurt yourself worse if you fuck up, it'll be able to cut clean through your nails instead of being stopped by them, it'll let you get away with shitty technique (which'll teach you shitty technique), and the edge won't last, so you'll spend half your life sharpening it.

A simple steel is all you need to keep a knife sharp, and a simple stone is all you need to fix a knife when you fuck up steeling it.

[Anonymous No.700561]

>>700560
>it'll be able to cut clean through your nails instead of being stopped by them

[Anonymous No.700567]

What kind of heater would work for a homemade kotatsu with the lowest risk of setting itself on fire?

[Anonymous No.700634]

Mower trouble. Engine won't start. Google says it's either the spark plug, some bit involving the pull cord itself, or the engine has seized. If it were the latter, wouldn't it stop me from pulling the pull cord? It's hard to pull, but it does pull, and it appears to turn the blades when I do.

[Anonymous No.700644]

>>700561
>pic
Fuck it, I guess this is my life now

[Anonymous No.700647]

>>685469
I was just looking for this guys site but I forgot his name other than afro, so thanks a ton anon

[Anonymous No.700650]

>>700567
Light bulb. Gloriously incandescent.
Or a small heat lamp.

[Anonymous No.700655]

>>700634
>Mower trouble. Engine won't start. Google says it's either the spark plug, some bit involving the pull cord itself, or the engine has seized. If it were the latter, wouldn't it stop me from pulling the pull cord? It's hard to pull, but it does pull, and it appears to turn the blades when I do.

Check and make sure nothing is wrapped around the blades.

Remove the spark plug and see what happens when you pull the cord with it out. Does gas come spewing out?

Has it been sitting for a while?

Reply back with findings and pic of mower.

Cheers.

[Anonymous No.700700]

>>699139

After the semi-success with the first transformer I've decided to try again winding this >>699163 one with thinner wires to achieve more resistance on each side in order to replicate pic related. But I have two questions.

I'm quite worried about the air gap since the transformer will be working on flyback mode and I'm not sure if that air gap could reduce its efficiency.
(I already got a reply for this, supposedly is to have a better control over the inductance, but I don't know if that's a problem when in flyback mode)


Since I don't know the gauge of the wiresI'll use a thicker one for the primary and a very thin for the secondary (as thin as a hair) and I'll eyeball the length required. I guess none of you know the gauge of the wires used in this kind of transformers.

I'll let you know how it went.

[Anonymous No.700701]

>>700700

If someone is interested I obtained the copper wire from very old relays, they even had different gauges to vay the resistance.

P.D: I got a cool post number.

[Anonymous No.700702]

>>700701

Here they are neatly winded, the one of the right has 1500 ohms but I can't tell the length, I'll have to take a 10 meter string and measure the ohms to theoretically calculate the gauge.

[Anonymous No.700895]

>>700655
Fixed it. It was just the pull cord. It was snagged on something, and I missed it because the first inspection was in low light. Unsnagged it and it started cleanly. Thanks for the help, though!

[Anonymous No.701185]

Hi diy homework tard here back again, I'm certain the person who wrote my EE book made a mistake? Hope you agree with me regarding pic related.

[Anonymous No.701186]

>>701185
I don't see any issues. A little abstract perhaps.

[Anonymous No.701202]

>>701185
>>701186

Don't see any problems here, either...

[Anonymous No.701217]

>>701202
>>701186

Thanks finally got it right.

[Anonymous No.701246]

kind of embarrassing question. I tried to drill something and the drill bit got stuck when the power was still on and the drill motor span around. Is there a chance I damaged my drill?

[Anonymous No.701247]

> Is there a chance I damaged my drill?

what can happen is that the coils overheat and burn out. or, some motors will have thermal fuses which will burn out.

but, since your drill still works, then there's no permanent damage.

[Anonymous No.701248]

>>701247
I heard a lot of metal sounds and my drill got extremely hot.

Also now it has a lower pitch and slower speed when I turn it on..

[Anonymous No.701276]

>>701248
you used up the battery

charge it

[Anonymous No.701277]

>>686040
Why make it pulse? Have it go off when it detects something. Someone walking by will cause the sensor to detect a change.

Keep it simple, nigger

[Anonymous No.701299]

>>688639
Lm741 is a generic all purpose op amp avaliable at radio shack, but not very good for audio. If you can order from digikey, I would recommend the lm833

[Anonymous No.701307]

>>700702
>>700701
>>700700

Success!! I could wind a 300R:8R transformer, which is way better than the one I made before ( 11R:0.5R ) I can get more sparks than before.

I couldn't wind more than 300 Ohms because I ran out of space (the transformer is quite small), but I'm happy with it.

I was lucky to have those relays at home, copper wire is terribly expensive.

[Anonymous No.701308]

>>700702
>>700701
>>700700

Success!! I could wind a 300R:8R transformer, which is way better than the one I made before ( 11R:0.5R ) I can get more sparks than before.

I couldn't wind more than 300 Ohms because I ran out of space (the transformer is quite small), but I'm happy with it.

I was lucky to have those relays at home, copper wire is terribly expensive.

But the first the capacitor of the cockroft multiplier died, I could see sparks glowing inside of it, and it's rated 400V!, that must mean the transformer outputs a huge voltage.

Thanks diy although I didn't get any reply.

[Anonymous No.701330]

>>701299
Have you ever heard of a source of noise which would cost pretty reliable disruption for a pre-amp circuit? I've tried a more transistor-based design, op-amp, many, but out of like 3-4 circuits none could amplify mic effectively, they would get some stupid background noise of a low frequency origin. I couldn't find the source.

[Anonymous No.701334]

>>699208
Anyone? I'll only have one of these speakers on hand and I don't want to fry the thing since it'll be a bluetooth device

[Anonymous No.701386]

How low can a 555 go? I'm going to be using a period of 45-60mins, and the schematic I'm basic the circuit on uses a 4.5hz with a 14-stage ripple counter, but I'm wondering if there's a simpler method (other than manual)

[Anonymous No.701397]

>>699208

Should work, albeit, as you've surmised, not all that well.

If you use an op-amp buffer to sense the line, you won't have to play with the volume or get any odd distortions (the forward voltage of the LEDs will cause some).

[Anonymous No.701412]

>>701386

I've used 555 time delays up to 30 mins, without any problems. well, the one problem is tweaking the time period, coz you have to wait a long time to see what the new period is.

[Anonymous No.701466]

Has anyone found a working bootloader (.hex) file for a PIC16F887a?

[Anonymous No.701469]

>>701397
Thanks, I'll investigate that further.

[Anonymous No.701475]

>>701466
Forgot to add, using 20mhz

[Anonymous No.701492]

>>701475
Doesn't that one have an internal clock/oscillator?

Just curious, but unless you're making a clock or a CNC with it, why not just use the internal one at 10mhz or whatever it runs at?

Admittedly, I'm a simpleton who likes to work down to as few components in a project as possible, to make it easier to comprehend.

[Anonymous No.701495]

>>701492
I'm trying to make a firefighter robot. I'm planning to use the PIC to do ADC conversions on some of the sensors it needs. I thought I should try to have as fast a clock speed as possible? Still a beginner.

[Anonymous No.701504]

>>701495

Faster clock speeds in general are good, simply because you have more clock cycles to work with. The question is whether or not you really need those extra cycles or if they're just wasting power, not to mention that you lose some pins to the oscillator.

For a robot that moves around, though, the wasted power is negligible because, for small microcontrollers, it's on the order of a few hundred microamps. If you can stand to use a pair of pins for the crystal, it doesn't really hurt to add it for the extra speed.

[Anonymous No.701507]

>>701495
>>701504
Thanks. That makes a lot of sense.

[Anonymous No.701582]

Are there cool projects I can do with a 5mW blue laser? Google didn't turn up much more than the fact blue lasers exist.

[Anonymous No.702229]

i want to make my cat live on my field so he can eat the rats, what kind of house can i build so he likes it and stays there ? also winter is coming

[Anonymous No.702282]

>>701308

The problem now is the secondary has so many windings it outputs a voltage high enough to cause a 0.2mm spark gap, or around 1kv. My shitty plastic capacitors are rated 400V and they are all just dying. I'll have to buy 1 or 2kV ceramic ones if I want it to last more than a few minutes.

[Anonymous No.702368]

Any way to create a square wave from a 3v input?

Bonus points if easily adjustable in the range of several kilohertzs.

[Anonymous No.702749]

>>702368
Showing results for low voltage 555
Product Index > Integrated Circuits (ICs) > Clock/Timing - Programmable Timers and Oscillators > TLC555CPE4

All prices are in US dollars.
Digi-Key Part Number 296-36160-5-ND
Price Break Unit Price Extended Price
1 0.85000 0.85
10 0.74600 7.46
25 0.66040 16.51
100 0.57510 57.51

Quantity Available Digi-Key Stock: 589
Can ship immediately

Factory Stock ? : 35,400
Manufacturer Texas Instruments
Manufacturer Part Number TLC555CPE4
Description IC OSC SINGLE TIMER 2.1MHZ 8-DIP

[Anonymous No.702815]

>>702749

Thank you google assistant.

I was searching about methods to create a square wave, I didn't know there were low voltage 555's.

[Anonymous No.703119]

Anyone know a good heavy-duty thread for clothing?