If I lay my powered board (UNO) on a non-conductive surface the onboard LED (13) will slowly fade out. Am I grounding the board somehow? If I let the board rest at a very slight angle it does not dim. What's going on?
images? video? Wires got disconnected? Using a 9V battery. Many things could be wrong.
Thank you for responding.
I power my board from a very stable Precision DC Power supply. I have no wires connected to it and yet when it is laid flat on a non-conductive surface the onboard led (13) begins to fade out. It really looks like a short but I can't see from where it might originate.
I'm sorry I cannot see what's happening either. Poo! Not being able to see the problem, I don't think I can be of help.
The circuit of the onboard pin 13 LED on the Uno is fairly sophisticated. As you discovered, this causes it to have a different behavior than we would normally observe with a standard circuit of an LED and series current limiting resistor in the case where pin 13 is in the default "floating" input state (equivalent to the state you would get from pinMode(13, INPUT)
in your sketch).
There is a good but possibly overly technical explanation of this circuit and the reason for it here:
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