Powering problem with nano and 4 relays
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Try running relay-ground through the arduino and not directly to source gnd?
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The fritzling looks ok.
Speculating: Could it for some reason pull too much from the gpios when controlling the relays?
If you have a multimeter, measure the current on one of the gpios, when turning on a relay.@hek The currunt is 0,002A from arduino pin4 to IN2 on the relay board
@sundberg84 Din't work with the GND from the arduino
Update it will only work when it's connected USB to the PC with the monitor program and remove the jumper on the relay board (JD-VCC - VCC current 0,308A).
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I think you should start by measuring voltage across VCC and GND on your Arduino pins when USB is not connected. On a lot of these breadboards "GND" and "VCC" rails are not connected the whole "width". Its not unusual that VCC is separated into two rails. Sometimes both VCC and GND are separated in the center of the rails.
Of course I can't see your actual setup but if it looks something like that image it can be a good idea to check connections between DC-plug and VCC/GND on you Arduino.
Worth a try.
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I think you should start by measuring voltage across VCC and GND on your Arduino pins when USB is not connected. On a lot of these breadboards "GND" and "VCC" rails are not connected the whole "width". Its not unusual that VCC is separated into two rails. Sometimes both VCC and GND are separated in the center of the rails.
Of course I can't see your actual setup but if it looks something like that image it can be a good idea to check connections between DC-plug and VCC/GND on you Arduino.
Worth a try.

