Hiwonder 4-Channel Encoder Motor Module
The Hiwonder 4-Channel Encoder Motor Driver is a small I2C motor controller with integrated encoder feedback for up to four brushed DC motors. It is well suited to small wheeled rovers (differential, ackermann, or mecanum) where size, weight, and a low channel count make a full-size ESC overkill.
PX4 supports the board via the hiwonder_emm I2C driver.
Features
- Four independent motor outputs with closed-loop speed control from on-board encoders.
- I2C interface (default address
0x34, 400 kHz). - Battery voltage telemetry of the supply rail powering the motor outputs.
- Selectable motor types (TT, N20, JGB37-520-12V-110RPM, or open-loop "no encoder").
Where to Buy
Hardware Setup
Wiring
Connect the four motors (with their encoder leads) to channels M1–M4 on the EMM and supply the motor driver from a battery suitable for the motors used. Wire the EMM's I2C bus (SDA, SCL, GND) to an external I2C port on the flight controller. The driver is hard-coded to bus 1 (the first external I2C bus) at address 0x34, which is the board default.
INFO
The driver auto-detects the four channels but the motor type is selected in firmware. The shipped default is JGB37-520-12V-110RPM; change HiwonderEMM.cpp (set_motor_type) if you use a different model.
Flight Controller Setup
Enable the Driver
Set the HIWONDER_EMM_EN parameter to 1 and reboot.
The driver is started automatically by the rover startup script (rc.rover), which runs for every ackermann, differential, and mecanum airframe. It is compiled into builds that enable CONFIG_DRIVERS_HIWONDER_EMM in the board configuration.
Actuator Allocation
The driver exposes a four-channel output group with the EMM parameter prefix. In Actuator Configuration, assign the rover wheel outputs (e.g. Motor 1, Motor 2, …) to channels EMM 1–EMM 4 matching how the motors are wired to the EMM.
The output range is fixed in firmware to 0..255 (the EMM's protocol range, internally mapped to a signed [-128, 127] speed command — 128 is stop, values below are reverse, values above are forward). EMM_DIS{i} (disarmed) and EMM_FAIL{i} (failsafe) per-channel parameters are user-tunable in the standard range.
Further Information
- Driver source:
src/drivers/hiwonder_emm - Actuator Configuration
- Rovers