Sunday, 11 December 2011

Battery powered hands warmer

If you ever had your hands frozen in the winter, you may be glad to have this simple battery powered hands warmer made from junk.

IMPORTANT: I take no responsibility for any injuries caused by anything you build using this guide. Everything you do is for you own responsibility. Be aware that this device may cause burns and heated batteries can explode !!!

To build this simple, yet useful device you will need:
- old PC power supply
- plastic 3 x 1,5V battery pack
- some resistors
- wires, solder, soldering iron

The most important element for the heater is the radiator with a power transistor that you should find in almost any PC power supply. You will need to unsolder the transistor together with the radiator. Mine was TT2140 which you can see on this image:

The circuit is very simple, it includes only the transistor and a 25 Ohm resistor. The value of the resistor may be different for different transistors. I suggest trying different values between 10 and 150 Ohm and measuring the current from the battery. The current should not be too high because the batteries will start heating instead of the transistor (and check if the temperature isn't too high for your hands). In my case I used two resistors paralleled, because I didn't had a 25 Ohm one.

Some more views of the heater:

Have fun and be safe !


Celal said...

Can I power this with a small wal adaptor as well?
I need to build it for soon.
Al Boz

Celal said...

can i use other power as well?