jremington:
So far. Still not a good idea.MOSFETs are far more energy efficient than the obsolete TIP120. Be sure to use a logic level MOSFET.
I just ordered them so I will change the TIP120. Thank you for your replies. It helps me a lot!!
I do have a followup question concerning the power supply. When the solenoid lock is activated the charging lights on my powerbank are turned on. When I connect a IR sensor to the same power rail nothing happens.
Furthermore if I connect a Robydyn mega mini board with micro usb from from the usb bank the charging lights also turn on. When I connect the Arduino Uno with a usb to the barrel jack this does not happen.
Can anyone explain why the charging lights are turned on and under why?