My setup is a RPi3 + Arduino Nano + WS2801 The conncetion seems fine. If I run a standalone programm on the Ardunio everything works as expexted. I can control the color of all LEDs. For Hyperion I'm using the following sketch I also tried this sketch - the inital sequence works, yet I still can not send any color manually My hyperion.config.json My log looks like this If I try to set a color with HyperCon or the Hyperion app nothing at all happens with the LEDs. They stay black. Maybe one more thing: If I sart/stop hyperion the LEDs dim up to light purple twice. /dev/tttyUSB0 is correct - that is the device that shows up when I connect the Arduino Any idea what could be wrong or how to investigate further?