Heated insoles

Hello.

I am a newbie in electronics and arduino. I would like to make heated insoles.
I looked in instructables.com and I saw this. Check it out:
How to make DIY heated insoles - YouTube

He said that nichrome wire, heat shrink tube, some wires, adaptor are needed. But I would like to see the temperature and adjust it as well as push button to turn on/off the insole heating as well as to run it with a battery.

I would really like to get some advice on how to build it and what materials, sensors, modules, etc I need to buy.

I am ebay fan so I would like to buy everything there and build it at home.

Some links of goods I got to buy:
some of heat shrink tubes: http://www.ebay.co.uk/itm/231578570566?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
nichrome wire: http://www.ebay.co.uk/itm/Nichrome-80-Round-Heater-Wire-0-4mm-26Gauge-AWG-32-8ft-Heating-ElementerCoil-/291569969389?hash=item43e2eca8ed:g:m0AAAOSw37tWCToo

And thats all I know what should I buy.

Could you give me some hint or links what I need to buy?

Thanks a lot!

I'd try it without any control, or just an on-off switch first. That's a lot easier & cheaper, and you might not need anything more unless it gets too hot.

The easiest way to measure temperature is with an [u]LM34[/u] (or LM35), and an Arduino of course.

You should be able to find examples of how to measure temperature and thermostat. Once you can read temperature, a thermostat simply requires an if-statement to turn the heat on & off.

You cannot power the heater wire directly from the Arduino. You'll need a relay, or transistor, or MOSFET to control the 12V and higher current.

If you want to display the temperature, you'll need an LED or LCD display.

You could use a pot to adjust the "target" temperature (with or without a display). i.e. There are lots of little plug-in heaters with a pot to adjust high-to-low that don't have an actual temperature display. And, there are heaters with a high-medium-low-off switch.

Nichrome wire comes in different gauges. Check the Ohms-per-foot spec (or Ohms-per-meter) and calculate the required current (Amps) with [u]Ohm's Law[/u] (Current = Voltage / Resistance). And in case you don't already know the power formula, Power (Watts) = Current x Voltage. And, power is directly related to heat.

Be careful with the power supply wire/ connection... If your feet are plugged-into the wall and you forget, you could trip! And, a 12V battery that can supply a 2 Amps for some period of time will be bulky and heavy to carry around.

I am ebay fan

I'm not, because you find a lot of stuff with incomplete specs.

Thats a cool sounding project! Are you going to have an external control or do you want it all in a small space somewhere on the shoe? Because it would be easier and you could have more features if you do an external control box.

Please say what type and I will try to point you in the right direction :slight_smile: