I want (eventually) to power my Arduino using MIDI inputs/output with a 9V adapter like this: adapter

MIDI also offer power but this seems quite unreliable (like 3V, 5V or uncertain, or none at all depending on the MIDI instrument).

Eventually I want to use 3 MIDI input ports, one output and (quite) some procoessing on an Arduino Mega.

  1. I heard ground loops in MIDI circuitry should be avoided ... is such cheap 9V adapter causing ground loops (or suspectible to do this)? Btw, I use opto-couplers but for power I need some external power.
  2. Is it anyway a good (or bad) idea to use a 9V adapter for MIDI solutions?
  3. What would be the problems if I use the power from MIDI?
  4. If I would want a 1602 or 2004 display module to be used, could I power it from the MIDI voltage pin or from the 9V adapter?
  5. If using the 9V adapter, is it a problem it runs at 9V while the Arduino runs on 5V? Should I get some extra circuitry or is this built in the Arduino already? Or are the pins working with +5v anyway even though a 9V adapter is used as power?

Sorry for maybe basic questions for you ... just I don't want to burn my Arduino (currently using an Uno, but ordered a Mega).

Thank you very much!

  • 1
    the spec doesn't tell us much, it's about the voltage source that feeds into it. 9v is fine for running an arduino. LCDs don't use very much current, so adding one won't make-or-break a setup. Input voltages are converted to 5v for GPIO. – dandavis Mar 25 '17 at 23:08
  • @dandavis Thanks for the info... Good to hear that input voltages are converted to 5v ... btw, GPIO, is that also all digital pins (like used for SPI/RX/TX etc?) – Michel Keijzers Mar 26 '17 at 8:48
  • 1
    yes, basically all the pins are 5v or 0v, save VIN and 3.3v. – dandavis Mar 26 '17 at 11:35

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