You can salvage some nice motors out of optical drives but they can be tricky to control ... His test circuit uses six 2N2222 transistors to protect the Arduino from excessive current.

Every time I log in, I’m presented with a list of new Blinky LEDs, Raspberry Pi accessories, Arduino ... Mega328 Transistor Tester Diode Triode Capacitance ESR Meter MOS/PNP/NPN L/C/R” in ...