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Turn 2 regular dc motors on and off with arduino safely? Answered

I have 2 regular old DC motors (one like this and one like this) that i need to turn on and off at the same time with an arduino. (No direction or speed control, just both of them full on on or full off.) I have a hacked computer PSU to power them and the arduino .

I have a bunch of 2n3904, 2n3906, and 2n222 transistors,a bunch of 1N914 diodes, a bunch of resistors, and some other random parts.

What other parts do i need and how do i do this easily, reliably, and safely?

Thank you!


I'd use a tip120 darlington transistor - radio shack has them for $1.50 or so.

Will handle up to about 5 amps - super easy.

Make sure to put the load (motor) between positive and the collector.

I also use a 100ohm resistor between the base and the arduino to limit current (not sure if this is really needed)

Might be a little late, but what you need is two logic level N-channel MOSFETs. Cheap, get 'em off sparkFun $0.95, and they can do on/off (no direction or speed control).

do you want speed control ? if not you can use relays. if so you will have to use a motor controler such as the l289 (what i use and handles 4 amps well) or maybe get a motor shield from adafruit (these seem to work well). also if they are really small and draw under 50mA you could just use the arduino pins

can you recomand schematic for a L289N controller? it will really help me, thanks.

If you want to make absolutely sure you don't damage the arduino, little relays would be the way to go. As it is, the transistors you have are too small for my taste, and I'd use a small power darlington transistor like a tip121 for my drivers.

What current do the motors take ?

I don't know. They are standard small dc motors that i ripped out of old toys. In my experience, they're nearly indestructible, so i'm not worried about burning them out. I just want to protect the arduino while powering them with 5v (the 12v on the psu seems to not be able to provide much current).