I have 8 fan modules that contain 2 fans per module. These 16 fans are powered by 12 VDC and are controlled by the PWM control pin.
The spec sheet for the fan module: https://www.delta-fan.com/Download/Spec/GFM0412SS-BL4F.pdf.
Microcontroller I am using: https://docs.particle.io/datasheets/wi-fi/photon-datasheet/
According to the spec sheet, I can output 3.3 V on the PWM pin of the MCU. This fits in the range of the PWM signal the fan reads. In the example in the datasheet for the fan, they place a 2 Kohm resistor between the MCU and the PWM pin. I believe I am reading the MCU datasheet right and it says I only get 100 mA that I can source on the PWM pin of the MCU. I would like to have all 16 fans running at the same speed.
How do I determine the size of the resistor to use on the PWM signal for one fan?
Can I use that PWM signal to control all 16 fans? If so how do I determine the resistor value?
If I can't use the one pin to control all 16 fans, perhaps a transistor would solve this for me. If so again no idea how to figure out the required resistor.
If you figured out the resistor value(s), please explain what I should be looking for on the datasheets so I know how to do this for other components in the future.