I'm debugging a problem with the Seeed music shield v1.0. I'm using an Uno. If I run things off of my computer's USB cable, all things work fine. If I connect a power supply, it can't init the sound card and opening MP3 files fail. I thought my power supply might be bad, so I bought another that out…

Strange behavior with power supply vs. computer USB power

LarryD August 6, 2013, 6:12am 2

With the power supply plugged into the Arduino, measure the voltage at the Vin pin, what is it?
Measure the 5V pin, what is it?

Topic		Replies	Views
Strange USB /UNO/play loop behaviour Programming Questions	5	244	June 13, 2023
Works on USB, not on PowerSupply Programming Questions	32	8102	May 5, 2021
Problem with external power supply to arduino IDE 1.x	14	10157	May 5, 2021
Problem powering my UNO from external power supply! Project Guidance	5	2188	May 5, 2021
Different program behaviour using external power supply / usb power General Electronics	6	1990	May 6, 2021