When you want to use the potentiometer knob to control the fan speed, you only need to connect the driver board directly to the 24V DC power supply. When you need to use the motherboard or to control, just take out the potentiometer, connect the signal pin of the driver board to the 5V or 3.3V pin of the motherboard, and connect it to GND. : enable "FAN_SOFT_PWM" and set "SOFT_PWM_SCALE"to 5 pin: host:gpio26 hardware_pwm: False cycle_time: 0.005 Color: As Shown Material: plastic Package Contents: 1 x Brushless Centrifugal Air Blower 1* Drive plate Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.