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Pi Sense HAT causing Pi 4 to freeze

naughtron

Good day all. 

I am running into an odd issue with the Pi Sense HAT and my Pi 4. The Pi 4 has been updated and ssh enabled. I have also configured the Pi to connect to my wireless network and have verified that WITHOUT the Pi Sense HAT attached I can ssh into the pi and run commands. 

The moment I attach the Pi Sense HAT to the Pi 4 everything appears to freeze up and my ssh connection no longer works. When I connect the Pi Sense HAT to the Pi 4 the LEDs light up in a rainbow patters (I assume this is its default). I am using an official Pi 4 power cord. 

Has anyone run into this before? I can't find any solutions online.

Thank you for your time. 

  • 0

    I may have the hardware to duplicate your conditions.

    What operating system are you using? I will blast an SD card and give it a try if you like?

  • 0

    Hi,

    It's not hot-swappable, it should ideally be connected and then powered up. Unexpected things could occur if it is plugged in while powered up, because some of the pins will make electrical connections before others have completed. This is unexpected (and very likely an untested scenario).

    There will be a spike in current draw when plugged in (the [normal] startup rainbow pattern consumes more power).

    I've not looked at the Sense Hat in detail recently, but there will be some capacitance on the board. You're essentially short-circuiting the power rail when you connect it, for a fraction of a second, and that could be sufficient to cause a brownout for the Pi.

    When you say you're using an official Pi 4 power cord, specifically, what does the power supply say on it (voltage and current rating). If you can attach a photo of the supply, that will help too.

    If you can test by shutting down the Pi, removing power, and then attaching the Sense HAT, that should work (i.e. that's a normal scenario that should work with the proper supply).