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Cooling Raspberry

  • Hi there,

    A few months ago I built my first MagicMirror.
    I am still satisfied with it.

    But, today I changed from Raspberry Pi 3 to a Raspberry Pi 3B+.
    The temperature always was a little bit too high before, especially in summer.

    Now I am looking for a solution to cool down the system using a mirror.

    The frame offers approx. 3-4cm height. So I tried a tiny 5V-fan, connected to RPi´s PINs 5V and GND. The fan was very noisy and had a high frequency. I would like to connect it to PIN 3.3V instead of 5V, so it rotates slower - which would be sufficient. But, I´ve read about a max. of 16mA/PIN. I don´t know how much energy the fan is going to consume. The fan was part of a cooling case for a RPi, which has to be connected to PINS 5V and GND.

    What kind of cooling solution would you recommend in my situation ?

  • Well I have connected the a simular cooling fan to the 3.3V Pin for the exact same reason and it works quite well so far. It’s been up and running for a couple of months now and I haven’t had a problem with it. So I reckon it should be ok 😉

  • Currently I am using a 40mm/12V fan which is just in front of the heat sink. The fan runs at 5V from the same source that powers the Pi. I ordered a 30x7mm 12V fan and 28x28x11mm heat sinks from Aliexpress for very little money. If hight is not an issue you can also get 15mm or even 20mm high heat sinks for better heat dissipation.
    The fan already arrived and is impossible to hear at 5V. It’s currently running on my 2nd Pi with a “hand made” heat sink from an old graphic card. In both cases the temperatures dropped at ~12°C.

    Maybe that’s an interesting solution for you.

  • Project Sponsor Module Developer

    @madscientist Sounds like a great idea!! If you can post pictures…that’ll be quite helpful 🙂

  • Module Developer

    I’m using ATB and I found this passive cooling case with Aluminum.
    It keeps under 55C without any annoying fan noise.


    I think there is an equivalent for RPI.

  • Module Developer

    Or you can consider this. I have one, but not tried yet.


    The fan be controllable by program and it’s own temperature sensor.

  • What are those costs for the case and the Pi power hat? My fan and heat sink will be together less than $2 and it’s absolutely silent as well with the same result. Drawback is that it takes time to receive the parts from China.

    I will post pics once I have everything but it still can take weeks to get the heat sinks.

  • Module Developer

    Expensive. 😃

    Anyway, I didn’t want to drain the power from 3.3V GPIO. As I’ve heard, Torques could give a harm to chips of RPI when it is connected to 3.3V GPIO directly.
    and for using 5V GPIO, to control its speed or on/off, additional relay circuit should be needed. I just had wanted a ready-made. 🙂
    And about the fan noise… case-by-case.

  • So, I bought a Nocutra 5V fan and coded a script like this:

  • I finally received my heat sinks and had the time to play with my second Pi (3b+, not my mirror-Pi, which is just a 3b).

    The heat sink is fixed to the CPU via heat conducting double-sided adhesive. It’s a small surface but it holds well. The 30mm 12V fan is connected to the 5V and GND of the Pi. That’s enough to get it running and it’s totally silent. The airflow is enough to keep everything cool.

    To fix the fan to the heat sink I just used some wood screws. Didn’t have any nicer looking ones…


    • list itemFan 1.17€ from Aliexpress
    • list itemHeat sink: 1.16€ (for 5 pieces) from Aliexpress, You can also buy just once but I will use the others for other projects.
    • list itemHeat conducting adhesive: 1.08€ for 48 pieces (25x25mm). You can buy less but I also use it for other projects…


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