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I have made a medical vending machine for my college project which can be used in remote areas to provide them with the basic medicines to help them deal with curable diseases and providing them the proper emergency medical kits as per the area statistics of prevailing diseases of the area. So I was using raspberry-pi3 for the project and to avoid the heating problem I had used heat sink and cooling fan but still I found after testing it for 2-3 days that I had to change the raspberry pi or would have to shut down the machine for some time else the system would start getting hanged and it also corrupted one of my memory card, I was lucky that i had backup of my project else i would have to implement my project from scratch again.

This is my RPI3 setup:

  • It's running the latest version of Ubuntu Mate.
  • It's connected to WiFi.
  • 5 inch Touch Screen HDMI Interface is used
  • 16gb memory card is used which is getting overheated due to high computing involved.

Any suggestions to solve this problem so it can be used in my machine for 24/7?

(Note - Please do not suggest to use any other costly device instead of raspberry pi as I am using it for college project.)

Suryavanshi Virendrasingh
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    Welcome to Raspberry Pi! Please take the tour and visit the helpcenter to see how things work here. Since someone is going to ask nonetheless it could very well be me, care to explain why a vending machine is doing heavy computing? – Ghanima Dec 20 '18 at 05:44
  • @Ghanima It is involved in high computing as it's using Deep Learning to verify the payment to detect fake currency and it is also connected with paypal to do digital transaction and as a part of project it will involve some government schemes to provide some medical kits in such remote areas, as a result we are verifying user through their fingerprint and their Unique identification Number. – Suryavanshi Virendrasingh Dec 20 '18 at 05:53
  • Thanks, interesting! First guess, if it overheats with heatsink and fan, make sure both are attached properly. Try venting the casing the Pi sits in, after all if the fan just stirs the air in a closed box it is not going to help much. – Ghanima Dec 20 '18 at 05:55
  • I must confess I am surprised that it is the memory-card that is overheating - what sort of temperatures is it reaching - and what is the ambient temperature? Pardon me for the gross assumption but from your name I am guessing that you are not located in a northern temperate zone but somewhere nearer the equator and some of us are probably not quite sure what climate conditions you are having to deal with! 8-) – SlySven Dec 20 '18 at 06:13
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    How do you know the problem is overheating? It is not clear from your question that you have ruled out other causes either (memory leaks, Current problems etc.) – Steve Robillard Dec 20 '18 at 06:44
  • Ghanima & @SteveRobillard I have tested it and from it I can say the problem is with overheating and I have properly attached heatsink and fan because before using heatsink and fan my device could barely perform properly for 3-4 hours, now atleast it is able to run for 2-3 days properly without any performance issue. – Suryavanshi Virendrasingh Dec 20 '18 at 07:23
  • @SlySeven Sorry your assumption is incorrect as I am from northern temperate zone, I am in the northern hilly regions of India ( In Himalayas.) – Suryavanshi Virendrasingh Dec 20 '18 at 07:30
  • I posted an answer, but now I'm also confused by the statement that it is the memory card that is overheating. You answered the part of the comment by @SlySven about your geographic location, but his question about the locality of the temperature fluctuation on the device still stands open. Is it only the memory card, or is the CPU overheating and distributing that heat around the electronics? – Brick Dec 20 '18 at 15:12
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    @Brick I think there got some misunderstanding due to my question, I am sorry for that. By overheating of memory card I mean that CPU is overheating and that heat is distributed around the whole device which results in making performance of device slower and memory card is also getting heated due to overheating of CPU. – Suryavanshi Virendrasingh Dec 20 '18 at 15:35

2 Answers2

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If you are overheating due to high computational load, your only choices are to compute less or dissipate heat better.

We don't have specific information to suggest how to compute less. Given what you've said, the only thing that comes to mind is to try to use a second Pi and distribute the computational load somehow. That will have marginally higher cost for the second Pi and require more engineering to handle the load distribution.

To physically dissipate the heat, you seem to know the options: Bigger heat sink, better circulation of air, or active cooling. Active cooling, of course, is potentially expensive. On the other hand, depending on the type medicines you're dispensing, you may already have refrigeration on the machine that you could use here, i.e. if you have a refrigerator unit to preserve medicines anyway, maybe put the Pi inside the refrigerator.

Brick
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  • The idea of using existing refrigeration is ingenous if it is present though you will want to hermetically seal the RPi to prevent condensation forming on its circuitry.

    However there is one tiny niggle - the questioner did say that they are using WiFi - unfortunately, the RPi3 series do not have an external WiFi antenna connection and if a refrigeration unit is being used it has a high chance of being a metal-box which is a good Faraday cage which can stop the WiFi working...!

     – SlySven Dec 21 '18 at 20:04
  • @SlySven I said put the Pi in, but course you only need to thermally sink to the refrigerator (if present). Probably the body of the Pi could be out and the heat sink somehow connected to the inside. Several ways to do it, but I agree that you don't want to blindly dump the electronics in the fridge without thinking this part through. – Brick Dec 21 '18 at 20:25
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The Pi3B is the most prone to overheating. If you are using a heatsink and fan there is little else to suggest without more detail of the product.

The Pi3B+ or 3A+ runs much cooler - but Ubuntu needs updated firmware.

Milliways
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  • I am using Pi3B, will using Pi3B+ be any help and what update firmwares will be required with Pi3B+ for Ubuntu that you have mentioned, Can you please elaborate – Suryavanshi Virendrasingh Dec 20 '18 at 07:33
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    @SuryavanshiVirendrasingh All the reports and my experience indicate the Pi3B+ performs better. I can not give detail of Ubuntu, this was merely a warning - Ubuntu is poorly supported on the Pi and has little support; it is probably not the best choice of OS - it can be made to operate but requires customisation. – Milliways Dec 20 '18 at 08:39