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Topic: Program not startin on external power input? (Read 4 times) previous topic - next topic

distorteddisco

Hey guys.

Basically, I'm running the Arduino board off of a 12V power supply, receiving MIDI and turning lights on and off.  The midi adapter is connected to RX.  The circuit works perfectly when the Arduino is powered off USB, but nothing happens when it's powered by the 12V adapter.

I thought I read that this was due to RX have a floating value, so I put a 10K resistor between RX and ground - this made no difference.

Thanks,
Drew

baum

Why does it have to be Serial? Just plug the midi adapter into a digital pin and pull it to ground. Activate the lights when the pin is pulled high. Unless the midi adapter is outputting true serial data at your baud rate, you may have some problems.

weirdo557

did you connect the ground from the midi adapter to the ground of the arduino? the signal may be using the ground from usb as a common ground, and when you take away the computer you disconnect the ground.

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