This isn’t a ST or Action Tiles issue, but I am hoping some people here can point me in the right direction. I have installed a few tablets around the house that are powered using existing low-voltage alarm wiring that was in the walls, but I have 1 more tablet that I want to install in a place that doesn’t have any of this wiring in the walls already.
There is a wall switch (with common wire in the gang box) there, so my plan was to wire in a small AC-DC power converter that takes the 120VAC and outputs 1A@5VDC, then run low voltage wiring carrying that up in the wall to a low voltage gang box 6" above that gang box where I would mount the tablet. I bought some right-angle micro USB connectors to solder on to the low voltage wire for this purpose so I could keep the tablet plugged in while its in the mounting bracket on the wall.
I decided to try it out once I got the equipment, so I soldered up one of the USB connectors (just connected VCC and GND- didn’t connect any other pins in the plug) and wired the AC end of the AC-DC converter to a plug. When I plug this micro USB connector into the Kindle Fire tablet, it starts to charge. Success! Except then I started noticing the tablet was becoming unresponsive to my input. I unplugged the USB, and it immediately became responsive again. I tried a standard wall-wart, and the tablet was fine. It just goes wonkey plugged into this custom charger. Uh oh!
My first thought was that I might have contacted VCC or GND to D+ or D-, so I checked with my multimeter on a USB breakout board. But there is no continuity between VCC or GND and any of the other pins in the connector, so thats not it. And I measure 5.12 volts DC between VCC and GND, so the power looks okay.
I’m kinda stumped here.