[danielheath]

I did a similar thing with a regular backlit computer screen.

It automatically shuts off after 30 seconds of inactivity.

I added a $3 webcam, and use openCV to detect motion. If three consecutive frames (sampled 0.5s apart) are each sufficiently difficult from the previous one, it attaches a virtual USB mouse, then moves it one pixel.

This wakes up the display whenever you walk past, then puts it back to sleep again when you stop moving.

The motion-detection pipeline uses less than 0.3% CPU on an intel N100 (6w TDP).

[jofzar]

You can probably just use a cheap motion sensor instead of the webcam if you wanted to. There so many now

[hipjiveguy]

If you have some to suggest, I'd love to hear it... TIA!

[danielheath]

Found a few aliexpress sellers offering LD2410C's, but all cost 30% more than the webcam I used.