I have a weird problem with my self-built Hyperion Ambilight: It shows rainbow colors when shutting down the AV Receiver and there is no HDMI signal anymore.

My workaround was to disable the entire construction (Raspberry Pi 3 + LED stripe) with a wall plug switch. The downside of this method is the system boot-up time so I couldn't use it as a typical lightbulb. Another downside was the fact that the Raspberry Pi doesn't like being turned off by pulling the power plug: It can destroy the entire SD card, but I was lucky and it never happened to me... Anyway, I need a better solution...