What's the default "on state" of Mote PHAT LED strips?


  • Raspberry Pi 4
  • Mote pHAT
  • Pimoroni Python library & examples from Github
  • Fan Shim

Whenever I boot or restart my Pi with two LED strips connected to the Mote pHAT, the strips light up a seemingly random range of their LEDs.

If I communicate with the strips from Python or run any of the bundled examples from Github all the LEDs work perfectly, the strips perform as expected and after running the examples they both clear down to all LEDs being off.

Is this expected behaviour? Should a random number of LEDs be lit up on boot? And if so - is there a simple way for this not to happen or for me to turn them off automatically when the Pi boots up?


I don’t own a Mote, just so you know. I do have a tone of other Blinky stuff, Unicorn Hat HD, LED Shim, Blinkt etc. They all stay blank on Pi boot up.
How is your soldering?
Phat firmly attached to the Pi?
Nothing else connected that is using SPI?

EDIT: Looking closely at you picture I’d say you have a soldering issue. It looks pretty bad if I’m honest.
The Ultimate Guide to Soldering - Pimoroni Yarr-niversity


Thanks. Why would everything work fine, but some random LEDs be on at startup? That’s what I’m struggling to understand.

Hard to say, make sure you don’t have two adjacent pins shorted together. It might be a signal from something else.

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One way around it would be to make up a python file that clears them, then run that on bootup via crontab.

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