Hey! I’ve got kind of a nebulous project in mind for this summer, and was wondering whether the Beagle Bone Black can easily power a normal computer fan. I have some extra 3-pins laying around, and have some kinda stupid ideas for how to use them. I’ve been told that the Raspberry Pi can’t supply enough power using GPIO, and wondered if the 'Bone is up to it off-the-shelf. Since these things are just simple 5v fans, I’m sure this question will sound silly to many, but i’m really new to electrical work and micro controllers. Any help you can offer is appreciated.
Uh. No. The I/O are 3.3V and they can deliver about 6 mA maximum.
Gerald
The BBB and RPi can be considered “controllers” in this aspect.
Lets say you want to use your BBB to turn on/off a 5v fan.
What you do is wire up a circuit with 5v going to a fan, with a NPN transistor in the middle. Even better would be an opto-isolator.
The transistor/opto-isolator would have the 5v source and Fan on the Collector, and ground connected to the Emitter.
Then you would connect up the Base of the transistor to a GPIO pin with a suitable resistor of course. You don’t need much current to trigger the transistor.
Then when you want to turn on the fan, then turn on the GPIO pin.
You would of course, want a diode around the fan etc to limit any electromagnetic “backwash” etc.
There are many pages on the internet that will tell you how to and why you should do this.
They explain it a lot better than I ever could.
Jerry