/diy/ - Do It Yourself

140V into an open circuit. what about into a 500ohm load? that's sort of what a tongue is. i bet it'll drop significantly. a gentle tickle, at most.

it will hurt a lot less than wondering for the rest of your life what life would be like ''if I only had guts''

by sticking large paperclips in the DVI connector, you can make the contact loose, so it wont make contact when it's plugged in. do it on the color input pins.

this is easy: with needlenose pliers just push in one of the pins for the RGB signal so the colors look all awful.

the best way to modify a mic for a particular purpose is to replace it with a mic especially made for that purpose. in your case, you'll want a PZM mic, coz these are best for recording an entire room.

http://www.uneeda-audio.com/pzm/

>>490288

your shit is all confused.

why are you using 2N3906 PNPs when the circuit diagram asks for NPNs, like the 2N3904? the way the circuit is set up, only NPNs will work there.

why does your diagram say "PNP Transfer"? that doesnt even make sense. i suppose the retard author meant "PCB transfer", and didnt double-check his shit before publishing.

i came up with an idea for dealing with variability in skin resistance: give a series of shocks with increasing power once every 10 seconds until the person wakes up and turns off the device.

to vary the shock, you'd use different driver circuits, each one with a different series resistor. but because you'd need a lot of transistors for this, I'd look for a chip for driving nixie tubes, like a K155ID1, instead.

> Are those in most brands or just the kind pictured?

every alarm watch I've seen has those springs. they connect with the buzzer which is on the watch's back plate. the buzzer is the yellowish circle on the right.

> What kind of amplification or conditioning would it need.

if the watch works at 3V, i'm guessing it should be able to drive an optocoupler directly. if it's 1.5V, you'd need a transistor switch, similar to the high-voltage driver I drew before. after the transistor, or optocoupler, you need a diode-capacitor-resistor-inverter gate to integrate the beeping pulses into one solid logic signal.

> an area of up to around 120cm^2

Ok, but i'm not sure how comfortable that would be. personally, i'd prefer to use something like the conductive rubber pads used, for example, by Dr. Ho's slimming machine, but these are like $40 a pair or something like that.

an alarm watch will usually have 2 springs to connect to the buzzer. these can used to trigger some circuit after some a bit of amplification or conditioning.

> has a higher surface area

you can get buttons up to 1.25 inches diameter from a sewing supply place.

this is the driver circuit. it's from memory, so may not be perfect. you'd need transistors rated for 250V, but not much current, so they could be fairly small.

as for the electrode buttons, you can place several pairs at different points to see where it works better. just snap the wires to test.

electrodes can be made from snap buttons. see pic. the left hand side ones would touch the skin, and the right hand side ones would connect to the circuit. to disconnect, just pull off, like unbuttoning a coat.

for placing the electrodes, it seems the most comfortable area would be the shin. you can get shin braces from the dollar store.

if you use a watch with alarm instead of a clock, then the whole thing could be self-contained in soft wrapping around the shin, with no external cables to get tangled.

> More seriously - I can check the voltage before I strap the thing on, just to be sure it is below the damage threshold.

actually, this is wrong. and you can trust me coz I'm a bit of an expert at shocking things. the thing is that the shock varies wildly depending on how moist or dry the skin is. and you cant predict that ahead of time. so, say you set it up like this:
- 200Vdc supply
- 5Kohm in series
- pulse width of 100usec
- 5 reps at 1 sec interval

you test it, and it feels powerful yet tolerable. but in the morning, it's hot, your skin is damp, and it's tortuous. another day, it's cool and dry, and you sleep right through it.

this variability it's a tough problem to solve, I'd go for a constant current source, but these are difficult at high voltages.

another problem I see is the use of a thyristor. you're better off with a high-voltage transistor (well 2 actually, an NPN to turn on a PNP) coz these can be turned on and off easily during a precise period. a thyristor has a mind of its own, when it comes to turning off.

> Where have I gone wrong?

I'm pretty sure your polarity is backward. that is B should go to C, and C to B. you probably got the idea of swapping the colors from the drawing in >>446514
but that's a special case, coz the idea there is to emulate a battery with a battery snap. that's why you swap the colors in that case. but if you follow the drawing all the way through, you'll see that the RED from the battery on the right, eventually comes out as a RED wire at the top -- the color swapping is only needed in an intermediate step.

> Any ideas?

make an adapter to drop the voltage, so you can power them from the cigarette lighter. if they're like mine, you need to wire the adapter to where the batteries connect to, coz if you connect it to the charger jack, they will not work while charging.

since you wanna also use them outside the vehicle using the built-in batteries, drill a small hole in the case to run the wires to the adapter, so that the batteries still fit.

also, download the manual to see if (or how) they can be used hands-free. more expensive models have a VOX function where they transit hands-free only when someone talks.

as the other anon alluded to, the distance specs are for ideal conditions, and bear little resemblance to reality.

>>438872

that's a good point that I forgot to mention in >>438870

555 is a standard part, so if it needs to be repaired, anyone can replace it, but a uP is a non-standard part, so can only be replaced by the original dude, if (1) he didn't misplace the source code, and (2) if the part is still being made, and (3) the programming dongle still works 4 versions of Windows hence.

penny stocks, by definition, can be manipulated by anyone with 10K to play with. so, you intend to go up against long-time players, who have a ton of experience suckering the little fish like you. and you want this to be your debut in the stock-playing world?

I wish you luck. you wont last a day.

> each streetlight has a sensor somewhere on it to tell when its dark, and the light turns on automatically

I dont believe this, coz when the lights go on, they all go on simultaneously for blocks up and down the street.

the way to disable a light is to open the access panel at the bottom, cut one of the wires, and install a remote controlled relay there. google this: SVAT WRC101 Wireless Remote Control Power Outlet Outdoor On/Off Switch with 100 Feet Range

you would need something equivalent to that but something made for the higher voltage used inside a street lamp.

a nice way to do what OP wants is to use silicon diodes in series with the load. each one will drop about 0.65V, so, for example, to get 11.7V, you start with 13V, then use 2 diodes in series to drop 1.3V, and you end up with11.7V.

the advantage over resistors is that it doesnt depend on current flow, so no need for trial and error.

You might consider the Polar Heart Rate monitor. The transmitter is worn on a belt around the chest, and the receiver is inside a watch worn on the wrist, so range is several feet.

The transmitter can be made quite smaller, coz you dont really need all the Heart Rate measuring circuitry, just the magnetic transmitter. I think I once traced out the schematic of the transmitter. No idea if I still have it. Newer versions use Bluetooth, I believe.

powering a radio from a switching power supply is a bad idea. yes, even, if you add a bunch of caps across it. the switcher has lots of high frequency signals whose harmonics are going to be caught by the radio circuitry, which works in the micro-volts at the antenna stage.

just a few days ago, I used a 5V phone charger to power a walkie-talkie, and it sounded like shit. with a linear power supply, it was fine.

also, have you noticed how hideous that radio looks? even a hipster would be ashamed to show that thing in their home.

Some stylish armor for the modern urban warrior.