Illuminated Touchscreen Poster Frame with Subliminal Message!

Step 14 Testing

Before plugging anything in, do one more check with a multimeter to look for short circuits and proper connections. Using the schematic as a guide, test between as many points as you can to ensure that everything is wired up properly. Make sure the electrode sensor wires are not shorted to anything. Most importantly, make sure there are no shorts from power to ground, on both the +12V and +5V lines.

Now, plug it in and see what happens. Be at the ready to yank out the cord should anything start to smoke (but nothing should, if your wiring is correct). Go ahead and test it - touch the sensors and see if the LEDs turn on.

TROUBLESHOOTING:

I'll admit, it didn't light up the first time I turned it on. I had some wires in the wrong place (the perils of working till 2 am!). Then I discovered a busted capacitor. Finally, I realized that the inverter was open-drain, so it needed a pull-up resistor on its output. If yours doesn't work, you should be able to diagnose most issues with a multimeter. Simply test the voltage levels at each point in the circuit, and look for voltages that aren't what they should be. If you do build this project, I'd also be glad to help with any troubleshooting!