This is a good project for anyone getting into electronics or wanting an idea for something cool. This isn't exactly a "cheap" project but its not very expensive either. The total cost for this project was £16.12 (~$25 at current exchange rate), about the same as a new mini fridge from the shops. If you do not have some of the parts mentioned, you will have to buy them. £38.58 is the total cost for all the materials brand new, but almost half my parts were recycled.The space inside the fridge is 10x10x15, big enough for normal sized cans, large cans, chocolate bars, carton drinks, capri suns(you can fit about 2 or 3), chocolate bars, or anything else you might want. I had some trouble finding a material that was cheap, a good heat insulator, strong, and easy to cut without shattering or being too hard. In the end I got a 50x40x0.3cm sheet of PVC from ebay for £5.98 including P+P. The fridge features an adjustable temperature dial (optional), fan cooled peltier plate, magnetic hinged door, and an LED light that comes on when you open the door.

Note: I never actually finished the fridge past step 5, I still have it lying around in my garage somewhere, but it worked as far as cooling. I wrote the instructable ages ago and as I am unlikely to finish it anytime soon, I decided to publish it as is.

Step 1: Materials

Here is a list of the materials you will need, and the UK prices, and UK places to buy.
The enclosure:
 -500x400x3mm White PVC sheet - £5.98 - Ebay UK (you can actually use a 400x400 sheet, but I would recommend getting a slightly bigger piece incase you make a mistake and so you can sand each piece)
-White Plastic 3 inch cupboard door handle - £1.29 - Ebay UK
 -Small Brass hinges - FREE - found in garage
-Small magnetic sheet - £0.69 - Hobbycraft (any thin magnets will do, but I wouldnt recommend the neodymium ones or you probably wont be able to open the door!)
-Small amount of scrap steel - FREE - I found an old sheet of steel in my garage and cut off some 2cmx1cm strips, and let them soak in white spirit and alcohol to clean them. Anything steel works, you could even cut up an empty coke can if you need to. Make sure it is real steel though and not stainless, because it isn't very magnetic and only contains about 2% iron. Real steel contains about 99% iron which is why it is so magnetic. Iron and nickel are also magnetic so they will work too, but may be harder to find and harder to cut.
 -Soft touch 6mm knob - £0.55 - Maplin (optional, recommended if you have a potentiometer for better grip and professional finish. I didn't buy one in the end)

The electronics:
-91.2W 40x40mm Peltier cooling unit - £3.37 - Ebay UK
 -Akasa chipset cooling kit - £6.96 - Ebay UK (you can also get them for £10 in maplin. All you need is an active chipset heatsink and a small flat passive chipset heatsink. MY heatsinks were actually recycled and the fan was bought for £2.50 on ebay)
 -Sub-miniature lever microswitch - £1.29 - Maplin (optional, for door light. Make sure it is a 3 pin one of a push to break one. This was recycled from an old project)
 -5mm 12V white LED - £1.29 - Maplin (optional, for door light. You can also use a lower voltage LED if you have a resistor. I actually got mine on ebay for the same price.)
 -Miniature Potentiometer 10K - £0.80 - Maplin (optional, but  recommended to control temperature. Any large value potentiometer will do really, it just needs to be able to increase/decrease resistance for the peltier unit. I didn't buy one in the end.)
-Single hole 2.1mm DV power jack - £1.69 - Maplin (or any other DC power jack to match your power supply)
 -12V DC power supply - This is not included in the parts/price list since I used a recycled computer power supply. You can use anything as long as it is over about 5V and under 12V. The peltier unit uses 7.6A of power, so remember wattage of peltier unit ÷ power supply voltage = Peltier cell amperage. If it is anything lower than 7.6A (which is probably is) Then the peltier unit won't be running as cool as possible, and this is ok, since we are making a fridge, not a freezer, but make sure it isn't too low. I will show you how to convert an old computer power supply (or new one, it probably works out cheaper)
-Wire - This also isn't on the price list because it is too cheap to measure and all good electronics hobbyists should have plenty of it
-Small amount of double sided tape and thermal compound, or thermal tape - not included on the price list since the amount you will use is unmeasurably small. You just need a teeny squirt of compound and a few strips of tape.

-Hacksaw, coping saw, or wood saw (or if you have one, a jigsaw or band saw)
-Drill (preferably a pillar drill, but a handheld drill will work just as well)
-Files (kind of optional but not if you want smooth edges. Alternatively you can use sandpaper)
-Hot glue gun (to stick it together, you could use a drill and screws or araldite/epoxy)
-Ruler, measuring tape, or large vernier caliper to measure the plastic
-Soldering iron
<p>Is there any picture of how the finished product would look like? I am planning to make this for personal use.</p>
<p>Is a 100W Switching Switch Power Supply Driver for LED Strip Light DC 12V 8.5A ok for the job ?</p>
If i use 8 modules how should i ise them in series?
<p>Are 2 same sized stacked Peltiers more effective/make a cooler temperature?</p>
<p>What do you mean by stacked? If you mean stacking them on top of each other, it wouldn't help too much. In fact, it might hurt the overall efficiency of the device you're trying to make. Normally with Peltier units, one side gets hot, and the other side gets cold. The bigger heatsink is used to dissipate the heat from the hot side of the unit to the outside, and the smaller heatsink will dissipate the cold from the cold side of the unit to the fridge. By having them stacked, I'm not too sure what would happen, but I don't believe it would change the results, compared to having only one unit.</p>
<p>I built one just like this I used a 12 volt 1 amp plug in AC adapter I had it all hooked up and it ran for less than 30 minutes when I checked on it my power supply was dead. I cut it open and found a thermo fuse had blown. The body of the AC adapter was quite hot. I am going to try a 6 volt 1.5 amp next but what is going to prevent this from over heating also? The Peltier unit I got on eBay says it is rated at 12 volt and 60 watt. Is the Peltier unit pulling more power then I can supply? I don't know what how much amps it needs. What can I do to prevent burning out the power supply?</p><p> hot to the touch </p>
<p>Hey, you might not need this anymore, but the reason your power supply got super hot and died was because the Peltier unit + all of your electronics wanted too much power for the power supply to dish out. Having all of those things on the same power supply caused the power supply to work very hard to meet the demands of your devices, which made it get hot and blow your fuse. By having something that draws near or more than the declared amperage on the power supply, it'll have to work harder to supply the power, meaning heat, and also risking blowing a fuse. Many fuses on power supplys will blow if too much power is being drawn from it. </p><p>So to put it in perspective, your Peltier unit draws 5 Amps on it's own. Adding in the current draw from the rest of your devices, at most, would give you 5.5 Amps total that need to be supplied to it. In your case, having a power supply that only supplies 1 Amp would give your entire machine 1/5 of the required amount of power, even though the power supply is working at it's max performance. This would then lead to a super hot power supply, and eventually a blown fuse.</p><p>If you don't want to do too much work, you could pick up a power supply that gives about 12 Volts @ 4-4.5 Amps, and that should work for your machine. However, at least by my understanding, the most convenient way to do it would be to hook up an adjustable resistor, or just a plain old resistor, directly to your Peltier unit, limiting the amount of current it's allowed to draw. This will allow you to use a greater power supply (say, 12 Volts @ 6 Amps) and not have to worry about it getting too cold or having too much power. </p><p>If you don't understand, I apologize, I'm not the best at explaining things like this... But I saw nobody answered your question, and I found it to be extremely valid for this project, so I did my best to answer it :)</p>
<p>For those who made it, how efficient is it with the pvc? I can't see it being very good, but I don't know.</p>
<p>You might want to educate yourself about stainless steel, because at the moment your ideas are erroneous. You have the composition wrong, and not all stainless steel is &quot;non-magnetic&quot;. Look it up and learn.</p>
<p>Soooo helpful! Thank you very much! got lots of good ideas for project!</p>
<p>Also: just for others to consider: you can get what is pretty much a perfectly pre-sized insulated container in the form of an <strong>Otterbox 2500</strong>: if you turn the Otterbox on end, it will sit flat, have a built-in &quot;door&quot; (the lid), has a &quot;top&quot; with a perfectly-sized square to accommodate a 40mm x 40mm peltier plate, is totally airtight and watertight when closed, and has just enough space in side to fit a soda can plus a bit to spare (inside dimensions 5.7&quot;x3&quot;x2.7&quot;) . Going now for <a href="http://www.amazon.com/OtterBox-Otterbox-Drybox-2500-Yellow/dp/B00EO72OO0/ref=sr_1_1?s=sporting-goods&ie=UTF8&qid=1406669512&sr=1-1&keywords=otterbox+2500" rel="nofollow">$20+ shipping on Amazon</a>, less if you can find one used. This would save the confusion and hassle (not to mention time) of trying to make an airtight PVC container as described here which might or might not fit together and work as intended when you are through. I have built one with just such a box, and could not be more pleased with the end result!</p>
<p>10x10x15 centimeters... Just for clarification. NOT 10&quot;x10&quot;x15&quot;.</p>
hey there would a 5amp 12V dc power supply work or is it too low?
That would be a little too low, thermoelectric coolers tend to be around 100w (8.3A at 12v) but you could probably find a lower powered up to 60W cooler to use instead. You could also just operate a higher powered cooler with the 5A supply and have it run at less power. 60W is probably still plenty for cooling drinks.
hey . can you tell something more about the peltier heat pumps . like what is the area they can really make cool and to how much temperature . and what is the rating of the peltier heat pump i should use . <br> <br>snkumar.nayak@gmail.com
Hi, the peltier cooling units work through the thermoelectric effect (google it) and consist of two plates of ceramic coated in the middle with a special substrate which I'm not entirely sure how it works. Basically, it has two wires coming out, you give it enough power and one side gets really hot and the other really cool. They actually work in reverse as well, if you cool one side and heat the other it'll give you power, but are a lot less efficient that way. <br> <br>For this application, the cold side is used, and the hot side must be cooled with a heatsink and fan to stop it decreasing the effect of the cold side. They aren't all that efficient, I'd recommend using a ~100w (this one uses a slightly less powerful one, about 92w) and it'll only cool a small space such as this mini fridge. I haven't really tested them fully, and wouldn't recommend using them for anything else, but they are unique little devices for applications like this.
how can i supply the required current and voltage to a device . snkumar.nayak@gmail.com
You will need a power supply that can supply high current power to the thermoelectric cooler. They are usually 12v and around 100w, so 100/12=8.3A. An 8 or 9 amp 12v supply would be expensive, so I recommend you recycle an old PC power supply (or buy a cheap one, it only needs to be relatively low powered and would probably be cheaper than just a 12v supply). <br> <br>If you short the green wire on the motherboard connector with ground (black, you can cut off all the other connectors so it's neater), then all the other power leads except one marked 12v (red) and a ground (black). You can then use these to provide high current power to the cooler. For current, it'll draw what it needs, you don't need the exact value for it to work. As long as it will provide more current than it needs (I say more, because if it's exactly the right amount, small fluctuations may cause it to try and draw a little more or less. It's usually not a problem, but some supplies could be destroyed by this).
For anyone building this and has a 3D printer, I've made a fridge body and door with window in SketchUp. ZIP folder with files is here: http://www.mediafire.com/?m7qzk9ck7lu4d4m
That's pretty awesome, thanks for that. Have you built a fridge using a 3D printer? Do you have any pics?
Nah mate, unfortunately I don't have enough money for a 3D printer, and most companies who do 3D printing want $900 just to print it :S
seem to be missing some pics of final assembly ;)
Yea, I never actually finished it. I wrote this instructable nearly a year ago and didn't publish it because I didn't finish the fridge past step 5. It is still lying around in the garage, I could just never be bothered to finish it. Maybe tomorrow.
reminds me of a mini bar fridge i fixed a couple days ago, except it had a larger &quot;hot&quot; heatsink and a fan on the cold side too.<br><br>i suggest if you finish it to put a good seal on the door, it goes a long way in getting it colder and keeping it cold.

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