Step 3: Attch a USB Cable

Picture of Attch a USB Cable
Peltier units are designed to operate at a voltage between 3-12 volts, and the 5 volts from your USB port work just fine. Although the amperage could ideally be higher, the 500 mw output is acceptable. Cut away the end of an old USB cable (or pick up a cheapy) and strip back a couple of inches of the plastic covering. Inside you will find 4 wires, usually within a braided or thin aluminum shield. The wire colors will be white, green, red, and black. Trim back the white and green wires, strip off a small bit of the black and red wires, and solder them to the red and black wires of the peltier unit. Wrap with electrical tape or use heatshrink tubing. If you need information on correct soldering procedure or the use of heatshrink tubing, there are many excellent Instructables that will gve you all the information you need, simply do a search!

Optionally, you can attach a 1K limiting resister in between the red and black wires, although you are quite safe at the voltage and mA to not really need one.

Now, plug in your USB cable to a USB port on your PC, and within about 30 seconds you will be able to feel one heatsink become very cool while the other becomes warm. Note which heatsink becomes cool, as that's what we'll want to encase inside the mini fridge.
amazehehe4 years ago
is there a peltier unit on the pc coolers? the ones with heatsinks
macman8085 years ago
is the peltier polarit protective because you could add a switch to change the polarity so that when the switch was flicked over the hot and cold sides would swap?
ALE7775 years ago
Dear Friend: What a nice proyect did you post! I want to make some similar fridge with a peltier cell I have buyed, but I am troubled with the attaching the heatsinks to both sides of the peltier cell... How did you attached the two heatsinks? Did you use screws? (Because in the photographs are not clear). If so, there aren't a small heat transfer across the metal screws? or there are other methods to attach the heatsinks? Anyone that can answer my request, sincerely, THANKS!!!
I didn't make a single drink cooler lol but cool idea, I actually took apart a coleman 12 v cooler and used the mini unit inside  of my computer case I just cut out the back side where the big fan was mounted and mounted the cooling system from the cooler there, I got the Idea when we were camping this past summer  when my buddy an I were talking about his computer over heating when he plays games that suck all the power his comp has to offer and his CPU was getting up to 120-130 degree's and shutting down, so beyond my wifes better judgement i ripped apart a 90 dollar cooler and did this, now my computer stays about 48 degree's F. and it works great.
oh yes I forgot to add you do need to insulate the case and use a air drying system for this to work properly I just used some 1/4 inch Styrofoam and covered it with anti-static plastic   to insulate the case
79spitfire6 years ago
A Peltier junction does not "generate" heat or cold, it transfers heat from the "cold" side to the "hot" side, much in the same way an air conditioner transfers "removes" heat from the evaporator and gives it up in the condenser, except the peltier junction has no moving parts. If I'm not mistaken, reversing the polarity of the unit reverses the direction of the heat movement on many units, so merely providing a switch to reverse polarity will give you a "cooler-warmer" unit so if your using your computer out in the cold, you can keep your coffee warm...
tyster6 years ago
Not sure how the current is controlled. There is a 500mW output, so at 5 volts, there is 100mA (0.1 Amps). My understanding of electronics is that the power supply, which is a voltage regulator controls the voltage, but the device controls the amount of current drawn from the power supply. If the peltier unit demands 5 Amps (2.5 Watts), then the power supply and USB channel would supply it and/or fry. Does the USB power supply have some sort of current limiter? In other words, if you short +5V to ground or allow a large current through, would the USB port be damaged?
The USB port has a current limiter, You have do get special electronics that request a higher mA from the USB port, But you can only request up to 500mA
z28se7 years ago
wow you can also make a warming device
tyster z28se6 years ago
I guess you could do both, Z28se. If a peltier units simply forces a temperature difference, then you could have two insulated containers back-to-back with the peltier unit mounted between the two. One side would be a little below room temperature and the other side will be a little above room temperature.
junits157 years ago
wont you need a fan for the hot side?