DC Motor & Fan

A small DC motor with a soft plastic fan attachment. Safe to touch, even when spinning.

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Background

The Grove Mini Fan is based on a DC motor and controller board. The module translates an analog input signal on the Grove SIG pin into a drive signal for the motor.

In practice, a PWM signal with a fast duty cycle works well. This gives you two simple ways to use the fan:

• As a digital on/off component, switching the motor fully on or off.
• With a PWM signal to adjust how much power the motor receives.

Basic Usage

This example uses the fan as a simple digital component. It switches the motor on for 3 seconds, then off for 3 seconds, in a repeating loop. The fan is connected to pin GP18.

# --- Imports
import time
import board
import digitalio

# --- Variables
fan = digitalio.DigitalInOut(board.GP18)
fan.direction = digitalio.Direction.OUTPUT

# --- Functions

# --- Setup

# --- Main loop
while True:
    print("Fan ON")
    fan.value = True
    time.sleep(3)

    print("Fan OFF")
    fan.value = False
    time.sleep(3)

Speed Control

This example uses a PWM signal on pin GP18 to change how much power the motor receives. The fan cycles through different power levels, pausing for two seconds at each step.

# --- Imports
import time
import board
import pwmio

# --- Variables
pwm = pwmio.PWMOut(board.GP18, frequency=25000, duty_cycle=0)

# --- Functions
def set_power(percent):
    percent = max(0, min(100, percent))
    pwm.duty_cycle = int((percent / 100) * 65535)

# --- Setup

# --- Main loop
while True:
    for power in [0, 25, 50, 75, 100, 75, 50, 25]:
        print(f"Motor power: {power}%")
        set_power(power)
        time.sleep(2)

Additional Resources

PWM in CircuitPython

Adafruit’s guide to working with PWM signals.