Need some help with a bit of electronics...

[PeterB]

... here's a pic: it's the innards of a USB electronic cigarette lighter.

http://i.imgur.com/8p8Fu6G.jpg?1 (bandwidth warning)

(Press a button, the wire heats up. Original, unaltered version here: http://www.amazon.com/Flameless-Electric...00R8MEYA0/)

... what I want to do is two things:

1) it has a small switch to turn on/off, I'd like it to be in the "always on" position... this seems easy enough to accomplish, just short the switch

2) apparently it has a program to automatically switch off after about 15 seconds (at which point the LED, indicated by "L" on the circuit board, begins to blink) ... I want to disable this "feature"... I'm wondering if it might have to do with what looks like a capacitor © on the circuit board. It's this second thing that I'm not sure how to do. (Maybe shorting a couple of pins on the IC?)

Ideas? TiA

[Filliam H. Muffman]

You want to disable the the auto-off? I would guess you are correct about the capacitor, either shorting it or removing it could disable the auto-off. Hard to say which to do, without knowing if the voltage across it goes up or down when it turns off.

[Bernie]

Capacitors charge. The time it takes to charge is usually the delay. Removal of the cap may solve the auto off.
The wire may not be up for continuous duty. The power supply to the device may not be up to continuous duty.
Is this a bomb?

[space-time]

He wants to put this is a solution to study some worms.

PeterB, you could connect that round wire directly to an adjustable power supply and start with a low voltage and increase until you see the worms swimming away. This thing is designed to light up a cigarette and may be too powerful if you start with the USB as power supply.

[Jack D.]

I don't know what your end use is but if all you want is a 'hot wire', this can be accomplished with some nichrome wire and a 9v battery. Kinda like a toasters inner workings. Youtube has a bunch of info on building these https://www.youtube.com/watch?v=C4BG56khKho.

edit: If your goal is to torture state secrets out of worms as S-T suggests then my solution won't work for you. However, there may be some ideas there that will allow you to build a lower/adjustable voltage device that will work for you.

[PeterB]

Thanks guys. Let me have a look at that YouTube... I had no idea people were jury-rigging stuff like this themselves...

[Paul F.]

You're making little hamster flamethrowers, aren't you?

[PeterB]

Hi everyone,

Ideally I'd be making a bigger ring of the wire, and I'd also need to make sure the wire doesn't melt (as it did in the video) ... so I guess I'd need a thicker gauge wire and higher voltage?

[space-time]

Lower voltage, longer wire.

[Filliam H. Muffman]

The wire has a fairly constant resistance per inch. With an adjustable power supply, you can make the size of loop you want and then slowly raise the voltage until the worms start moving away. Radio Shack used to have one for about $40, but they are no more.

You could use a wallwart USB charger and then experiment to find a diameter/length of wire that got hot enough while not overloading the charger. It looks like at least one company sells it on Amazon for DIY vape. http://www.amazon.com/Genuine-AtomizerWi...B00TIZHY3O Edit: one company has a chart of ohms per foot for different diameters. http://www.arcorelectronics.com/uninsula...ance-wire/