Hi, this is Wayne again with a topic “Personal Cooling Unit”.
This week, i’m going to show you how you can make a personal cooling system that can help you survive the hot days of summer. This system uses a thermoelectric cooler. These are basically small refrigerators that are able to turn electricity directly into a change in temperature without any moving parts. When a current is applied to the unit, one of the plates gets colder and the other will get hotter. You can use the cold plate to chill a soda or to cool you down the best place to apply. This kind of cooler is the inside of the wrist at the radial artery.
There’S a lot of blood flowing near the surface. This helps to distribute the cooling effect throughout your whole body. For this system to be effective, we need to add two things: a heat sink to help cool down the hot plate and a second plate to disperse the cooling over a larger area.
On the wrist start, by measuring the dimensions of your thermoelectric element, mine was 40 millimeters by 40. Millimeters now find a heat sink. That’S slightly larger than this also get a piece of 1 16 aluminum plate. That’S at least a half inch larger than the thermoelectric element on each side. We’Re going to attach the heat sink to the aluminum plate with a pair of machine screws, so mark the locations of the mounting holes onto the plate and drill holes that are slightly smaller than the screws. Now we need to add screw threads to the holes.
Normally you want to use a tap for this, but if you don’t have a tap the right size, you can take a couple of extra screws and tightly screw them into the holes. This will ruin the screws, but it should carve a decent set of threads into the plate. Next, we need to bend the plate so that it roughly matches the contour of your wrist. I just used a pair of pliers to bend the two ends up to help. Keep the thermoelectric unit insulated, i added foam around the outside. You want to use heat resistant foam for this trace. The outline of the thermoelectric element and cut it out then fit the foam in place and trim off any excess around the sides before assembling all the pieces. It’S a good idea to apply a thermal paste to the plates. This helps to fill in any air gaps and improve the conductivity. The last thing that i added was a small fan to blow over the heat sink. This can be any small 12 volt pc fan to hold it in place. I just used a pair of bent paper clips.
Now you need a way to attach the cooling unit to your wrist. To do this, i used a pair of fabric straps with velcro to attach them to the plate. I used another set of machine screws now just hook up a 12 volt power source and you’re done, but if you want you can take it one step further and make it adjustable to do this. I made a simple control circuit. A 555 timer sets how frequently the cooler is turned on and a relay connects and disconnects power to the unit. After testing the circuit on a breadboard, i solder the parts onto a printed circuit board, then i trim the board so that it could easily fit inside a plastic project housing. Well, that’s how you can make your own personal cooling system, thanks for watching and check back soon for more diy hacks and how to’s .