Hacking HDMIPi power switch with Feedback #piday #raspberrypi @Raspberry_Pi
Raspi.tv posted a follow up to their how to hack the HDMIPi Power Switch tutorial- check it out here.
In a recent post, I showed you how to hack the HDMIPi power switch so that you can turn the screen on and off from the Pi.
But no sooner had I done that than my friend Peter Onion, wondering if there was a way to detect if the LCD is on or off in case it gets “out of sync”, tweeted this…
…and that was all I needed. Well. That and a multimeter. I started carefully probing the various 3-legged semi-conductors on the HDMIPi board. I thought it would take a long time to find what I was looking for, but it only took about 10 minutes. I found a transistor where one leg reads 0V when the HDMIPi LCD is on and 3V3 when it’s off. Perfect!