I have a 5 V 3-pin fan. I want to be able to:
- power it from an Arduino Uno or a Seeeduino Lotus board, and, ideally;
- be able to change its speed.
Most resources I can find on the web explain how to connect a standard 12 V fan and moreover complicate the thing by explaining how to get the speed of a fan or to control multiple fans. This is way too complex for me.
If my understanding is correct, I can't just connect a fan to analog output pins, because the absolute max power per pin is 40 mA (recommended: 20 mA), while the fan uses 100 mA.
Instead, I have to somehow connect two of the three pins of the fan to an external power, and use the third pin to control the speed. Am I supposed to use the ground and 5 V pins situated on the left side of the board above ANALOG IN?
If not, what are my other options? The board is powered by an USB cable, and I see no way to split the power at this level between the board and another device without running a risk of damaging the board.