Adafruit N20 DC Motor with Magnetic Encoder - 6V with 1:100 Gear Ratio

The first step in robotics projects is getting a motor spinning. However, not all motors operate at the same speed, even with identical part numbers, due to variations in voltage, environment, and manufacturing. The next crucial step is determining the motor's speed, a challenging task simplified by adding an encoder wheel and an optical or magnetic counter. As the motor turns, the encoder wheel spins, allowing the counter to detect each spoke, enabling speed calculations. Enhance functionality by adding a second counter to determine direction.

This motor streamlines the process with an integrated magnetic wheel and two Hall effect sensors. As a compact N20-sized motor, it operates smoothly with 4.5 to 6V DC power. Connect the white and red wires to your motor driver for speed adjustment and direction control using PWM and an H-bridge. The blue wire connects to your microcontroller’s ground pin, while the black wire adapts to any 3-5V DC source. Hall effect outputs are accessible via the yellow and green wires.

An Arduino example sketch is provided but can be adapted for other languages. It involves interrupting one of the encoder pins, counting the time since the last interrupt, and multiplying the count time by 14 counts per revolution and the gear ratio. This motor features a 1:100 gear ratio, uses 6V nominal power, and draws about 100mA (200mA when stalled). The gear ratio impacts torque and RPM but not current draw.