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In the year 2000, Ben Heckendorn built his first mod.
“Ben: We can rebuild it smaller, better, portable.”
Since then, he has continued his work helping those in need with creating new projects. If you’ve got an idea you’d like to see built, why not send it to The Ben Heck Show.
“Ben: Hello and welcome back to The Ben Heck Show, in this episode we are going to try and build a super fast can cooler. To accomplish this we use a cooling device called a Peltier. These work by passing a current between two different types of metal. Heat is absorbed at one junction – the cold side, and passed through to the other junction – the hot side. This is known as a Peltier fact. By pulling heat away from the hot side, we can keep the other side very cool which will allow us to chill objects with it, such as a can of pop or soda depending on your vernacular and location. Let’s get started.”
“Ben: You know I was just thinking making this automatic can cooler might waste a lot of electricity so we should probably keep an eye on how much we are using during this episode. Let’s get started.”
“Ben: So when I heard of the project Super Fast Can Cooler, the first thing that I thought of using was a Peltier Module. Now what this does is it basically takes heat from one side and blows it out the other, so you can cool things here or heat them here – but usually it used for cooling. Alright, so this really isn’t hooked up very well but it is enough to show us what it will do. I put the Peltier on the heat sync, this is going to be the cold side so right now it is 64°, so let’s fire it up and see what we get. Look at that sucker drop. Here is an example work-flow so to speak. You’ve got the object you want cooled here, you’ve got some sort of medium that connects to it, we are probably going to have a heat sync shaped like a can but for now this. So the object you want to cool is here, so what happens is the Peltier sucks the heat this way so it goes here, here, then this blows the heat away – so it is kind of like a heat tunnel.”
“Ben: So what I am going to do next is a cheapy little experiment, is hook up some of these heat syncs together using some J.B. Weld which I am out of Arctic Silver. We will see if we can use it to directly cool down some water and that will sort of prove our concept, and from there we will work on how to design and control a can cooling system. And of course I am going to use way more than I should, just like sugar and salt. There we go – just a spoonful of sugar, something something. So now the J.B. Weld is doing its thing. It is actually J.B. Kwik so I only have to stand here for like six minutes. It has obviously been on there long enough so the next thing to do is to attach this fan. This is basically how it is going to be like this. Look ma – no hands. So the basic idea is this kind of snaps over these pins and then the fan will bolt to that – that way it is all one module. Okay, now I just need something that I can set this in that holds water so I can try cooling the water. Allison, do you have any ideas?”
“Allison: Well if you go Arby’s for lunch, maybe you can grab a cup or something from there.”
“Ben: Ah, oh – when you get the roast beef sandwich to go it comes in a plastic thing that opens up, we could put water in that and set that in it.”
“Ben: Okay I am back from Arby’s, we are going to do a very scientific experiment. We have this Arby’s tray which will hold some water, and we will put a precise amount obviously in both of hot water, and then what we will do is stick one on the cooling device and the other one we will just leave open and see how rapidly it changes. This is not really as dangerous as it looks, okay you can definitely see a difference already in the water temperature. Obviously there is not a whole lot of surface area on this heat sync to pull it out of the water, but after about two minutes it is doing a difference. Okay, so the next thing we need to think about is how to control the temperature of the can cooler.
You will stick a can in and then it will activate and then it will cool it until it reaches a certain temperature. So what we are working with here, we have an Arduino Nano system and as you can see it is pretty small and you can fit it into a socket fairly easily. Then we have two other components on the board, we have a temperature sensor which uses and I²C bus which is basically a two wired data transfer bus, as you can see right there. And then we have a mosfet - mosfet is metal-oxide-semiconductor-field-effect-transistor. What this will do is we can pass the high current Peltier voltage through this and it can be activated by the Nano. So the Nano will send 5-volts in this line which will allow the current, high current, to go and power the Peltier.
Then once it senses that the can is cold enough, it will deactivate the mosfet and beep or something. So we have got these numbers scrolling by and they are not changing, so I am wondering if that is actually the temperature or if I am reading the wrong register. We are getting data off of the little device, but is it the right data. So let’s use this blow torch, ahhhhhh – there it goes, look at it go, yeah! Alright, so we have interfaced the temperature sensor with the Arduino and now we can use it to control our Peltier.”
“Ben: So this is room temperature, or shop temperature Pepsi – so we are going to see what temperature it is, program that into the Arduino as a starting point, and then give it a target temperature such as 10° cooler, and then make the Arduino shut itself off once this reaches that temperature.
We’ve got the code in the Arduino so we can unplug it from the computer. Remember it is has its own non-vol powered RAM so it will remember the program basically forever until you update it again. So as long as this sensor is above 45°F, this mosfet is going to be active allowing this thing to cool it off. So what our program is going to do is if this sensor is above 50° it will activate the Peltier and the fan via this mosfet, and you will know it is activated because this LED will be on. Once this temperature goes below 50° it will turn off the mosfet and turn off the Peltier and the fan. So right now for instance, it is going to be warm enough and so this stuff activates.
I will rapidly cool it here using some handy Wisconsin snow, okay you see it turned off. So this shows that once the liquid or whatever cools off to a certain – whoa, temperature it will turn off the circuit. Well, let no Pepsi go to waste. Yeah, mmm – delicious. So we have shown how to use a Peltier how to cool something, we have also shown a microprocessor such as the Arduino can be used to control that cooling using a temperature sensor and a mosfet to start it and stop it. In the next section we will build the actual physical can cooler itself and make it look like some sort of product.”
“Ben: Being able to tell the temperature of something without actually touching it is a very useful thing to have. I mean your fingers are great and all, but they won’t give you a very accurate reading. High quality FLUKE infrared thermometers like this one, can be purchased for around $100 and are very useful for the shop, kitchen or garage. That steak is that temperature, my engine block is that temperature, I’m that temperature. One thing to note though, sometimes these thermometers aren’t very accurate when you use them on bright shiny objects, as we saw in the episode when I attempted to measure the heat sync we built. Testing temperature when you work on a project is a good idea, because if you need to add any heat syncs or change the design in any way you can do it before you glue anything together or close it up permanently. If you are not sure if an object is too hot to handle, pull out your FLUKE-62. I’m – you can handle me.”
“Ben: This CNC machine is now the ultimate power in the universe. I suggest we use it for pinball. There will be no one to stop us this time. I will make the most powerful pinball machine ever. I will even learn to keep soldiers from dying. Do what must be done.”
“Ben: Whom do you serve?”
“Jason: Team Heckendorn.”
“Ben: Let’s test this temporary flipper circuit. Jones is going to simulate pushing the button on the cabinet, already we are beginning to get the LED lit up. Now he is going to simulate the end of stroke switch. Okay, so what happens is when you first push the button it uses the high powered coil and like bam hits the ball – once the ball is up it hits the end of stroke switch so that it knows the flipper is all the way up and then it switches to a lower power circuit. Okay, so we are going to direct test here. There is a 50-volt power supply, which goes into the solenoids and the solenoids drain into these mosfet’s, so you saw the LED lighting up before – so what happens basically is this will switch on the mofet’s and allow certain circuits of the solenoids to trade to ground and that will active the solenoids. So using this multi-meter we will see how much amperage it draws by pulling the flipper directly off the 50-volt power supply.
Then we can see what the peak current is for the mosfet’s. It is possible that the mosfet’s are insufficient for the amount of power we need. Okay, ready? 4.1 amps. Okay so we are going to try to direct drive these not even using the mosfet’s to see if that is our problem. Okay, ready? Release. Ooh, that seemed pretty powerful. Alright, so I hooked up this really simple mosfet circuit, so we can see if it is the mosfet or the programming – we are basically simplifying to see where the problem is. We have the high current of our flipper going into our cheapy mosfet, going to ground. Okay, activate the high voltage power supply. Hmmm – don’t worry, next time in Pinball Wars we are going to really get some stuff done.”
“Ben: So now it is time to build the actual can cooler unit itself. We have already demonstrated how it works, so now we are going to CNC some actual parts. Okay, the aluminium is all milled and there is all these spare chips, but what should I do with them?”
“Ben: It seems all very handy but there is still a lot of work we have to do by hand, ah.”
“Ben: I should have thought of this before I routed out the sheet, breaking up the surface so we can glue it together better. Oh well, almost done. I have to wash them off because of all of the oil and the microscopic or very hard to see sanding aluminium bits won’t help the glue stick. So what we are going to do next is build this heat sync, and I am going to glue these pieces together, and stack them up basically so they go around the can. The bottom pieces have screw holes because they are going to mount to the rest of our mechanism or slide. Alright, so there are our pieces. What do you get for the engineer in your life who has everything? How about an aluminium can cozy.”
“Ben: The next thing we need to do is make a frame to enclose it. What we have here is a side drawing representation of how it is going to work, I am going to get some large heat syncs off here directly, basically off the shelf because those heat syncs can suck a lot of heat, far more than we need them to. They are going to go on either side, this square pelt her represents the CR unit, and how it contacts with the aluminium. So now we are going to make the frame which will hold the heat syncs. This will be a welcome break for the machine after all the aluminium it routed. Alright, so we have routed out the pieces, let me just kind of show you how it is going to go together – this part here slides back and forth, and it connects to that. This part doesn’t move, the can sits on it. And these things right here s where the heat sync base is. Okay so before we attach this heat sync to the sliding platform, I am going to use my tap to put some screw threads on the inside of these holes. That goes there, that goes there – I think I should be able to drill some holes in this and make it match this pattern.
That should work – and then the Peltier is almost exactly the right size to fit in here. So I could actually use Arctic Silver instead of J.B. Weld and then fit this in here and then screw this in so this would be held on by the compression of the screws. So we are going to put some threads in here too so we can tighten the heat sync against it and hold the Peltier. Alright I am going to put on the Arctic Silver, it didn’t quite fit. Alright, so now we are going to screw the heat sync in place – you know what this could also do on those hot summer days, hook it up to your arm and cool off your entire bloodstream in minutes. Okay, I am now going to try switching this on. We have one of the units made, basically we need two of these, total but the basic idea is this should become very cold and all the heat will be sucked through this heat sync, through the heat pipes, and blown out this way.
Here we go. Okay we are reading 57° but that can’t be right because it is much colder than that. I think it is because the IR doesn’t work on this aluminium. But, we are actually getting condensation on it now so we are definitely taking a lot of heat out. Alright so we have got one of these assemblies done, so I am going to bolt it onto the frame here. This side will be stationary and the other side will come in and clamp to this. I was worried there wouldn’t be enough support here for the heat sync, but it appears to stand just fine, so I think I will just leave it like this. Let me show you how this is going to work. And then another one of these is going to be here so the can is going to be hit on both angles.”
“Karee: Hi Ben.”
“Ben: Well, if it isn’t my dear baby sister Karee.”
“Karee: I was wondering, I was really thirsty could I get a pop?”
“Ben: I would love to help you but the only one I have is this lukewarm one that is in the microwave.”
“Karee: Well, I would kind of like something cold.”
“Ben: This little puppy here will make all your dreams come true.”
“Karee: Can’t wait.”
“Ben: Just put the pop here.”
“Karee: Okay.”
“Ben: Squeeze this side on, and it will be encapsulated in solid aluminium and cold before you know it.”
“Karee: Wonderful.”
“Ben: So yeah, it uses Peltier’s which use the Peltier Fact – similar metal causes cold to happen, and then the custom milled heat sync. You got all this?”
“Karee: Yeah.”
“Ben: It pulls all the heat out of the can, and blows it into the atmosphere, so it doubles as a room heater.”
“Karee: Yeah.”
“Ben: Here you go, a chilled can of soda.”
“Karee: Thanks it’s about time. Oh, that was the coldest soda, best soda I have ever had in my life.”
“Ben: That is all the time we have for today. In our next episode we will be building a new version of the portable workbench you may have seen in past episodes. But this one is going to be Better, Faster, Stronger. We will see you then.”
The Ben Heck Show is made possible by our sponsors at element 14. For more information on all my projects and for a list of all the parts I used today visit element14.com. We will see you next time.