Hey everybody. If you’re looking for a way to run your Magic Mirror with one power cord, I might have a solution. When I first started working on my first Magic Mirror, I was looking for a TV with a USB port that could power the RasPi, so the finished product would only need one power cord. I’ve read a lot about how the USB ports on most TVs don’t really supply power and so they won’t work for this purpose. Eventually I decided I’d have to figure a different way to get it all to work with just one cord, and would deal with that problem later.
Anyway, I went to a pawn shop to see if they had any cheap flatscreen TVs that I could use for the project, and they had a few of these Sceptre brand TVs for about $30 apiece. I grabbed a good looking 19” widescreen, bought it, and took it home.
Just for the hell of it, I decided to see what would happen if I plugged a RasPi 3 into the USB and HDMI ports. I turned the TV on expecting to be disappointed, but it was not so! The TV turned on and the RasPi booted up! No low power warning at all! I tested it out by playing some games on RetroPie and it worked like a charm.
My buddy came over with his multimeter and we cut an old usb cable in half to see what kind of output the USB port was giving and it was a steady 5.2V and 2.1A! Now that I’ve got the Magic Mirror software up and running, I’ve tested it by leaving it on first over night, and then overnight and all next day while I went to work, and there were no problems!
It doesn’t work with a RasPi 3B+, though. I get the low power warning and it won’t boot. But it works great for the regular 3 and 0.
Hope some of y’all find this useful and helpful!