The Electric Heated Sweater

Introduction: The Electric Heated Sweater

About: We are a group of Engineers, Tinkerers, Designers, Programers, and Nerds ! ---- and Since April 2011 We also have a Cupcake Maker

Hey Guys welcome to our Entry for the Sew Contest Ins. We made an Electric Heated Sweater that uses a 9v battery to heat up your sweater. It works great yall should give it a shot. Just make sure to follow the instructions and you use a sweater that you dont really love! cuz you wont be able to wash this sweater EVER AGAIN!

 Important safety point: only use this is a  pure-wool sweater, or one with proven heat resistance.  Many synthetic fibres melt at surprisingly low temperatures

Visit our website at for additional videos and projects. We hope you enjoy what we did :) 

Step 1: Getting Your 20 Gauge Wire

You have to meassure your 20 gauge ENAMEL copper wire to your desired lenght. Usually about 5-6 feet. This really depends on the size of your sweater :P

Step 2: Start to Weaver Your Sweater With Your Wire

The next step is to start to weave your sweater with your copper wire in a zig zag motion. You will be using the Copper wire instead of a needle and thread Start your weave from about 1" from the top and 1" from the left shoulder. (or right depending on how you look at it)

You have to make sure that you weave in between the two layers of your sweater, you dont want it to make contac with your skin or you could get burned, very unlikely but it could happen.

You need to go all the way to the right (or left) then go down 1" and come back to the other side, then go under again 1" and go back. repeat this process till you get about half way down because anything bellow that is more of a hastle than anything.

you will end your zig zag at the bottom right and then weave your way to the top to about 1" by 1" from the corner.

Step 3: Repeat Step 2 on the Back

YOu need to repeat the sames steps on the back of the sweater in the same pattern (zig Zag)

Step 4: Connect Your Copper Wires

Connect your copper wires from the back of your sweater and then connect them to the front using a 9v battery connector.

Step 5: Attach a Switch

you need to cut one of the wires on your 9v holder and install a switch

Step 6: Make the Pocket and Put the Battery In

Make a small pocket to hold a Small Tin Can inside it. You dont have to do that but we REALLY recomend you using a small tin box just in case the battery explodes or something ( we have had our sweater for 3 days and it still has nothing wrong) 

 Attach the switch onthe side of the tin box and place it inside of the pocket. You need to then hook up your battery and put the battery inside the tin box and close it.

Step 7: Turn on Your Switch and Feel the Heat BABY!

once you get the switch on the ON possition you will feel the coil begin to warm up after a couple of minutes. It worked great and it actually can get pretty hot but it works amazing.

Specially if you wear a jacket over the sweater it works better and it hides the battery. The coil can only be seen from an angle or under extremly bright lights. Enjoy your new sweater and hope you like it ! Dont forget to visit our website at



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    28 Discussions

    you r basikly just short curcitingt the battry so ovcorce its going to heet up.wold using a camra circut work ?

    1 reply

    Well, Using a camera circuit output's a very high voltage to recharge the capacitor for the flash circuitry. The circuit does not output enough Amperage to heat up a copper wire enough for it to do significant heating.

    Short circuiting the battery? Not really, because the battery has something to output to, and takes longer for it to actually get to the battery, it will heat up, but not because it is short circuiting. It would heat up slightly (or even more than slightly) because of the discharge of electrons that were stored in the battery.

    I decided to experiment with this before I tried "sewing" it in the clothing. I took a 3 foot piece of 22 gauge enamel coated magnet wire. (It's what i could find) I soldered on a 9 volt battery connector making a simple loop. I used no switch for the experiment. When I connected the battery, the only thing that got hot was the battery. Any thoughts as to what I did wrong? It's a great instructable and I hope to be able to make use of it but really need some help, please. Thanks.

    7 replies

    That happened to us too several times, we took the idea from a website a long time ago and the first few times we were unable to figure it out. We know you have to use very THIN, magnetic wire maybe? it works with the same principle as a heated blanket but with much less power. If the battery is getting hot, dont risk it it could explode. Maybe add two batteries ? I wish i could be of more help I'm sorry


    When you say add two you mean in series or in parallel? Oh... the wire I used was 22 gauge which is actually thinner that the 20 gauge you used. Could it maybe be that there wasn't enough resistance for it to heat the wire and therefore the battery got hot?

    I think that might be the problem... I wonder if adding a diode at the end of both terminals work?

    for one thing, the resistance is actually greater in a thinner wire, which could "burn out" more easily (try the same test with steel wool.) The diodes may work, but it seems unlikely. sorry to burst your bubble!

    emanb29 thanks for your contribution but I am unclear as to the solution here. I know what you mean about steel wool. When hooked to a battery. It actually burns. Ruben suggested putting two batteries but I don't see how that would fix the problem of the battery heating up. Is the problem that the smaller gauge wire increased the resistance and the battery heating up was in response to needing more "push" to get the electrons from one terminal to the other and adding a second battery will give that increase? Any helpful suggestions would be appreciated as I am very interested in this idea!

    Possibly, I should say some sort of insulated thick (16g or so) wire should heat w/o heating the battery. High-insulation wire is used in stoves, so possibly if you pass less current through teflon insulated wire it wouldnt be TOO warm. "Microwire" supposedly works but I don't know where to get it.


    After much research on this project, I discovered the reason for my failure through use of ohm's law. Using 18 feet of this wire (enough to make a lattice over the back) My 9v would need to supply over 48 amps, about 43 more than the battery could according to the datasheet

    Might i suggest a dc-dc boost converter instead of a 9v battery. if you need more power for longer than set up more batteries in a parallel. (NOT SERIES!!). you use the fuji joule thief circuit (pirate labs method is better than josepinos...josepino gets very close...but removing a few more things from the circuit increases wavelength output).

    If you get a standard 4AA battery holder and modify it so that the batteries are in parallel and NOT series (so input is still 1.5v) you will output about 20-60v...depending on which method you use. some people get more than that too. and the battiers last longer than your current method.

    now, why not go through a little more and make the unit detacheable? take a thin cloth and attach the wiring to that, put some velcro on it and attach on the inside of the sweater. now you have a patch and you can use on multiple clothes.

    anyways, hopefully this is helpful for you guys. cool idea too.


    enjoy peeps!!

    check out overunity"dot"com and look under joule thief
    get your basic design from and modify using overunity.

    hope you guys enjoy!!!


    1 reply

    I was wondering if you could substitute a charger that puts out 6v at 500mA for the battery?

    I am no electrician, but this seems a little dangerous.  Firstly, the people who would need this are diabetics and there is a disease where the body cannot control its own temperature.  This means that it would probably get too hot a burn them because they are less sensitive to heat.  Secondly, the plastic is going to get hot and melt.  Have you ever used a soldering iron and seen it?  Overall, it is pretty cool, just not safe.  I, personally, would make a circuit with a few resistors to control how much heat you wanted

    2 replies

    you dont need a resistor if you use the right size battery. if you check the resistance of the wire used then you can figure out the current. if that is too high, then use a resistor. if not, there is no need

    If you wanted it to be rather strange, you could attach a small wind turbine to the front of the jumper, so when it is cold and windy, it heats up, otherwise it stays off!

    only 20 mins of use here. if you use rech 4 X D size cells, about 1 - 2 hrs of use.