Only first few leds light up and in a random fashion

[sharkyenergy]

Hello! I dont seem to be able to get it to work. I tried with a raspberry 2 and also with a raspberry 1. My leds use a ws2801 chip, and are confirmed working since they work with other scripts.

I do not get any errors from the script, but only the first few leds light up and show some random colors. It looks like the spi output rate is off... Could that be? Can you help me fix it?

Thank you

[meeotch]

I successfully used PixelPi as the basis of a project built around an rPi Model B about ten years ago. I recently tried to run it on an rPi 400, and got similar results (only the first few pixels lit up, colors were wrong). But the project still ran fine on the Model B.

I ultimately concluded, as you did, that the SPI clock speed was probably the culprit. Googling suggested that this speed is adjustable, but in the end, I decided to try Adafruit's updated WS2801 library, which is built on top of CircuitPython. It lets you treat the LED strip as a sequence, and write colors by simply setting sequence elements/slices. It seems to work with no adjustment to the SPI clock.