Summer is hot. Especially if you are being active outdoors. So to avoid getting overheated, I made a simple thermoelectric cooling unit that attaches to your wrist. This is able to rapidly cool your entire body.

You can use this to cool down after a workout or between plays. The unit is small and easily portable. All you need is access to electricity such as a 12 volt battery.

Step 1: Watch the Video

Here is a video walkthrough of the project.

<p>thanks for sharing this information. You know this very interesting. I was reading on a similar prototype was created in 2013 by four students from Massachusetts Institute of Technology (MIT). surely you know, it is the famous bracelet Wristify. Interasada I am currently doing a similar project. I want to take these prototypes to poor areas of my country, where temperatures are aggressive. I am from Peru, and since I read about wristify, this project interested me since I was looking for a way to reduce the deaths of poor children in my country, by intense cold (frost) and heatstroke. While searching I found this work and caught my attention as I saw in this work an alternative to somehow help my people. It sounds crazy, but I want to.</p><p>I am electrical engineering student, so I want to. I want to make this more portable design and be able to control it with an Arduino module (I could help with some information about that. The MIT used the module INTEL Edison. I want to use arduino) ........ While searching for information I found your page and I'm glad. thanks for sharing. If you could help me with some information to better this design, I'd appreciate it (how could control the temperature at a rate of 0.4 &deg; C / s. Thanks).</p>
<p>If your goal is to help the poor in your country, you are going to want to focus on making it low cost. Arduinos and thermoelectric elements and batteries are expensive. I would highly recommend using something like an evaporative cooling system with water. This will make it much more accessible to more people. </p>
<p>This is neat!,</p><p>Can the System be adapted to cool the soles of Feet?</p><p>Because I suffer from Burning Feet, Nor can i wear any socks/Shoes due to the same. The Place where is live is very hot (40~43.C Summers, 25~35.C winters)Some cooling at feet will be most useful.</p>
<p>I had to improvise a bit since my budget was tight at the time, but I managed to make it work using an old smoke alarm for the circuitry housing and 9 volt battery contact. Fun project!</p>
<p>Can i use a 5V battery as a supply?</p><p>Will the cooling be effective??</p>
<p>A thermoelectric element should work at 5 volts. You just need to make sure that the fan can work at 5 volts. Most computer fans are designed for 12 volts,</p>
<p>Hi, </p><p>Is it possible to use a smaller battery in order to have it portable? Thinking of building the initial part without the control circuit. Therefore having it as a cooler but nothing more than maybe an on and off switch. Having it all in one gadget if its possible with a small battery.</p><p>Thanks.</p>
Yes. You can do it with a battery. The cooling unit that I used was originally designed to work with a car outlet. The only thing to consider is how long the battery will last. Take the capacity of the battery (usually labeled in mAh) and divide that by the current rating of your unit. This will let you know about how many hours the unit can be powered by the battery.
<p>Hello.</p><p>I like your project, well done, i would like to make this project in order to get heat from the plate, so i have to switch the positive and negative wires, but i have one question.</p><p>I would like to chose the temperature of the plate, there is a way in order to do this? how voltage and heat are connected?</p><p>takns.</p>
Think of the thermoelectric unit as a heat pump. You put electricity in and it pumps the heat from one plate to the other. This makes one plate cold and the other plate hot. The amount of energy that you put in determines how much heat can be moved from one plate to the other. It is based on watts not voltage. And the final temperatures depend on the temperature in the room and if either plate has a heat sink. The manufacturer will probably list some kind of temperature difference (between the two plates ) that the element can create. I hope this helps.
<p>Thanks for the answer, i guess that i will must use a LM35 in order to get a defined temperature.</p>
<p>Reverse it for winter! :D</p>
<p>Ouch my eye itched, dang that smarted.</p>
<p>I think the module used here is most common TEC12706. The thickness of the cold side heat sink is about 1.6 mm, but the area looks large and three dimensional conduction will come into picture, so temperature will vary across area on the cold aluminum. </p><p>Assuming normal thermal paste, and this 12V fan, the COP of the this system should be approx. 1.3~1.5 on wearing on wrist (34 deg. C on body ) and ambient 27 deg. C conditions.</p><p>By the way, there are no proven researches of wrist cooling affecting core body temperature yet. There are few , which slightly lowers the core body, but for that, we need to cool whole wrist and palm throughout circumference.</p>
<p>Such Products are already in Market by Indian Manufacturer (www.dhamainnovations.com), and that too without fan. </p>
<p>Did you try with anything under 1/16&quot; thick aluminum plate first? Just wondering if you chose it from testing. Also I was wondering if the fan was necessary. It looks like the prototypes for the wristify just used the heat sink. Just curious! Working on putting mine together just waiting for the timer to come in. Thanks for the instructable :)</p>
I chose all the parts that I used because it is what I had lying around my shop.
why not put it on chest or back??
The arteries in your wrist are much closer to the surface. So it cools you down faster.
laptop cooling fan is better ...
laptop cooling fan is better ...
<p>This is awesome, but is there a way to do something similar, but with the heat side of the cooler? You know for winter and such. </p>
Switch the positive and negative wires of the power supply and disconnect the battery. A thermoelectric cooler is the same thing as a thermoelectric heater. They are just wired up in the opposite polarity.
<p>Ah ok. So with that said, would it be possible to along with your temperature adjuster to add a switch that basically does that? </p>
<p>Yes, get a double pole double throw switch (DPDT). Connect the center terminals to the cooler/heater. Then connect the power to the terminals on each side in the opposite orientation. That way it effectively switches the polarity when the switch is flipped.</p>
<p>Cool!! Reminds me of this: https://www.youtube.com/watch?v=vQ5rEbSK8tE</p>
<p>So what kind of on/off timing does that circuit give you?</p>
The on time is about 7 seconds. The off time varies based on the potentiometer.
<p>Really? Interesting. I would have figured it would have an equal on/off time based off the pot. Kind of silly, but how does it do the 7 on, variable off?<br>This makes things much easier, by the way! I mentioned the Wristify in another comment, and was looking to make one based of an arudiono, but this will be so much simpler and cheaper!! </p>
<p>The capacitor charges through R1. When the capacitor voltage is 2/3 of the supply voltage, pin 7 connects to ground and the capacitor discharges through R2. When the capacitor voltage reaches 1/3 of the supply voltage, pin 7 is disconnected and the capacitor begins to charge again. During the charging cycle the output at pin 3 is high and during the discharge cycle the output is low. The value of R1 determines the length of the &quot;on&quot; time and R2 determines the length of the &quot;off&quot; time.</p>
<p>Awesome! I never realized the 555 was that versatile! Yet another silly follow up: could you just stick in two pots in the places of the R1 and R2 to have complete control over the on/off times?</p>
<p>So crazy it's cool (pun intended), I woulda gone with headband tho...more hipster cool. Thanks for the detail, some of the best I have read.</p>
Nice man, that cooler is boss
<p>This is a really well-written Instructable. The steps are logical and methodical, and the pictures are really clear and on-target. After reading this, I am confident that I can make one of these.</p><p>My wife has carpal tunnel tenosynovitis (something like that) and needs to ice her wrists frequently for pain relief. This device would be very convenient for us. Thank you. (I have been waiting for Wristify to get their act together, but they seem to be degrading over time.)</p>
<p>haha, nice, but is that comfortable? :D</p>
This one is rather large for everyday use around the house. It is more like what you would use at outdoor sporting events. But you could easily make one half the size. Or you could build it into a chair or wrist support for your computer.
<p>awesome :D</p>
<p>Realistically, this is useless, but this operational principle can be very helpful in some projects, although, nice idea! :)</p>
<p>Actually, it's not as useless as you would think! I was shocked to learn that (if done correctly) this manner of cooling is actually rather effective. Instead of it always being on, though, you'd want to pulse the element on and off. The skin on your wrist never fully gets used to the cooler temp, and your body will reflect that. I get the feeling this was heavily influenced by the MIT project Wristify, which uses this very concept.</p>
Well, I didn't know about Wristify 'till now, at first glance it seemed to be useless, but actually it is pretty smart solution to trick you body so you can feel more comfortable. Thanks for explanation!
<p>Disregard the &quot;instead of always being on&quot; remark. I goofed and didn't read the ible before commenting.</p>
Wy did you at the resistor to the mosfet? It is useless, because a mosfet works with voltage and not with current like a normal transistor does. I would also remove the relay and at a larger mosfet to switch the fan and the peltier.
You are right. The resistor isn't really needed. I just left it in so that people can substitute a power NPN transistor and it would still work.
<p>Very nice, but you will get extra hot and tired carrying a big battery around :)</p>

About This Instructable




Bio: My name is Jason Poel Smith I am a Community Manager here at Instructables. In my free time, I am an Inventor, Maker, Hacker, Tinker ... More »
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