Powering the Arduino with 12 volt and tapping the Arduino 5 volt to power a relay board is wrong. The Arduino 5 volt converter will not give enough current for that.
Feed the Arduino with the 5 volt You have in the build. Connect to the 5 volt pin.
Powering the Arduino with 12 volt and tapping the Arduino 5 volt to power a relay board is wrong. The Arduino 5 volt converter will not give enough current for that.
Feed the Arduino with the 5 volt You have in the build. Connect to the 5 volt pin.