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In this instructable I will show you how to build a small fridge with a peltier cooler. The fridge can cool one aluminium can down to 3 degrees celcius.

For this instructable you need the following material :

If you want to build a PCB you also need :

  • Pin header connectors
  • Screw connectors
  • PCB
  • Jumpers or cable

If you don't want to build the circuit on a PCB you need :

  • Breadboard
  • Jumpers

You can find the most material on used electronic devices. My heat sinks and fans for example are from CPU coolers.

Step 1: Assemble Cooler

Take the big heatsink and attache a fan. After that put a bit of thermal past on the back side of the peltier cooler and press the module on the heatsink. Finally put the smaller heat sink on top of the peltier cooler with thermal past. You may also want to put a piece of carboard between the two heatsinks to insulate. I also add tape at the side on the heat sink to optimise airflow, but I'm not sure if it's helpeful.

Step 2: Build Circuit

To control the fridge we need an arduino and some electronics. I built a circuit on an experimental stripboard PCB, but you can build it on a breadboard if you don't have a soldering iron.

To avoid bad connections I put a piece of tape at the bottom of the MOSFET heatsink. I added copper wire to some copper strips on the PCB to avoid overheatink

The last picture shows the diagram of the upper side of the PCB. Each
circle is a hole in the PCB and each cross an interuption in the copper strip.

The circuit assume that the arduino is powered by the USB cable of another external power source (not the 12 volt). You can change the circuit and add a voltage regulator or a DC - DC converter to step down the 12 volts to 5 volts.

Step 3: Programming

After the hardware is done, let's start programming. For this you need to download the arduino software.

Copy and past the following code in the editor : https://github.com/postronium/peltier-fridge/blob... .

Befor uploading your code select the right connector in "tool -> port" and select the correct arduino board in "tool -> board".

Explanation of the code

The code reads the voltage at the A1 pin. This voltage represents the target temperature. If the target temperature is lower than the temperature at the sensor, the pulse width is set a bit bigger. If the target temp is bigger that the temperature at the sensor, the pulse width is decreased.

Step 4: Connections

Connect the power on the right connector, there are 4 connectors to connect the fans. Connect the peltier module on the left.The red wire is the "+" and the other the "-". If, for one reason the module work in reverse (get hot where it schould be cooled) you can reverse the polarity.

Solder wires on the "Adafruit TMP36" sensor and connect them to the 3 connector on the PCB.

Step 5: Usage and Safety

Plug the module in the Arduino and connect all the wire, be sure to have wire and a power supply that can provide at least 4 amps. If you built the circuit on a breadboard with jumper wire you shouldn't draw more than 1 amp of current.

Be sure to don't go over the Peltier module current limit. This limit is something about 5 or 6 amps for most of the 12 volt modules.

You can see the Arduino log message with the Arduino software. Go to "tool" -> "serial monitor" in the Arduino software to see it. (see picture)

To cool the hot heat sink efficiently let some space between it and other objects in order to have an optimal airflow.

Be careful short circuits and overheating can hapen, use a power supply with short circuit protection.

I'm not responsable for any damage or incident in any case.

Thank you for reading ! Feel free to ask questions or suggest improvements in the comments section below.


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<p><a href="https://drive.google.com/drive/folders/0B3h5yByDJORycWV2aS00VFlaTTQ?usp=sharing" rel="nofollow">Download All Eagle PCB Files Here :)</a></p>
<p>EDIT: My PCB uses the Absolute-BARE-MINIMUM Parts so you can free up your Arduino to be used as prototyping in another project</p><p>Then build your own PCB specific to the job, Thus freeing up your Arduino again to be prototypes in yet more projects :))</p><p>The BARE-Minimum Parts for Arduino in my Schematic are:</p><p>ATMEGA328P-PU (with Bootloader)</p><p>16 Mhz Crystal + Two 22pf Capacitors</p><p>Two 100n Capacitors</p><p>Two Resistors (10K Pullup &amp; 1K LED Resistor)</p><p>One Momentary Switch</p><p>One 2x3 Pin Header Row</p><p>One 1x6 Pin Header Row</p><p>And Thats it !!</p><p>Of Course ive added a Power Supply circuit too, so the extra parts are;</p><p>Two Electrolytic Capacitors</p><p>Two 100n Capacitors</p><p>One 7805 Voltage Regulator</p><p>One Heatsink</p><p>One 1K Resistor</p><p>One LED</p><p>So if you buy the parts in Quantities of 5 - youll end up being able to build 5 Arduino Projects for the price of ONE Arduino Board lol !! Roughly priced like that :)</p>
<p>Howdy <a href="https://www.instructables.com/member/postron/" rel="nofollow">Postron</a> &amp; well done, an awesome write-up/ible !!!</p><p>EXACTLY what i needed to keep my water in my computer watercooling loop as cool as possible, motherboard has been lacquered so not got to worry about condensation :)</p><p>i see you use Fritzing, very nice illustrations from that software, i use it too, but also, Eagle CADsoft (Free-Version) which makes making PCB's such a pleasure due to massive parts libraries, do give it a try if you havent already :)</p><p>Working on a Single Sided PCB for this - for Homebrew, but also a scaled down version for Double Sided to be professionally made :)</p><p>Ive got the rough schematic and board design made, will post up an instructable for it and Link you Directly as receiving full credit for this design &amp; code :)</p><p>i actually want to cool down 2-3 parts of my setup so multiple boards is what i need, plus will be needing even more to cool down some Alt-Coin hardware lol</p><p>Included the Files so you can mess with them too, they are only my 1st attempts and thanks for the awesome inspiration !!</p><p>Ive added 2 heatsinks and theres only 1 Wire needing to be plumbed on the top side of the PCB, the rest is all single sided for home brew PCB making :)</p>

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Bio: I'm a Swiss student likes to build things, especially electric or electronic projects. I also like programming: websites, applications and algorithms. Postron is a ... More »
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