Thanks Paul, I just ordered a bunch of irl530s and 47k resistors and am very much looking forward to try that out. I also wonder if there might be a way to use somethig like a switch between the arduino and the solenoid/voltage. So that I don't need a transistor and an arduino pin for every solenoid I want to control but can toggle power on and off for every single solenoid with just like 2 pins. Any idea is very much appreciated!