Things You'll Need
2 9-volt batteries
2 9-volt connectors
Solder and soldering iron
50 feet of 22ga nichrome heating wire
Needle and thread
2 long wool socks
Roll of adhesive heat-resistant tape
There are hundreds of different home electronics projects. Many are doable at minimum cost with very little equipment. But how many are practical? It might be a lot of fun to build your own radio or tinker with the circuits in a toy keyboard, but those projects are just for entertainment. If you are pragmatic, you could try making some heated clothing. Heated socks are a good place to start, as they keep your extremities warm. The novelty is a plus, too: who do you know who owns heated socks?
Cut your nichrome heating wire into two even parts. You should have two 25ft segments, once for each sock.
The 9-volt holders should have a place for the connector's head (the part that attaches to the battery) to slide in. Attach each connector to each holder.
Solder the end of one wire segment to the positive lead on one of your 9-volt connectors. Do the same for another wire segment on your other connector.
Begin threading the wire through the first sock. Poke the wire through the fabric like a needle. You want to thread about 3 inches of wire in, then poke the end back out about an inch to the left. Repeat this as though you are stitching a circle around the ankle. The rest of the wire should be poking out just below the entry point.
Thread the wire back through and repeat step 3 an inch or so lower on the sock. You're stitching the wire in and out like thread, forming circles around the sock about an inch apart. Leave enough wire to attach the other end to the negative lead on the 9-volt connector.
Wrap the free end of the wire in heat-resistant tape to keep it from touching any of the coils and shorting out the wire. Solder the free end of the wire to the negative lead on your 9-volt connector.
Repeat Steps 1-5 for the other wool sock. Use the heat-resistant tape to attack each battery holder to each sock if desired. To heat your socks up, simply attach the 9 volts to the connectors and wear them over a thin pair of long white socks.
Experiment with different wire lengths. Remember that longer lengths confer more electrical resistance, which means longer warm-up time, lower temperature, and longer battery life. If the socks are too hot or the batteries die too quickly, use a battery with lower voltage. If they're not hot enough or take too long to warm up, use a higher voltage.
Plug the battery in and let the socks sit on a non-flammable surface in order to test them. A mistake in wiring can cause burns or fires.