DC Motor

Description

DC motor drivers are available on the following module:

OI-Dc (x4)

Main characteristics

Bidirectional control: Supports both forward and reverse rotation.
Variable speed control: PWM-based speed regulation with duty cycle from 0% to 100%.
Current monitoring: Real-time current measurement for each motor.
Fault detection: Hardware fault pin monitoring for driver protection.
High current capability: Designed to drive DC motors with appropriate current ratings.

The OI-Dc module uses H-bridge motor drivers to control DC motors. Each motor driver has two control inputs (IN1 and IN2) that are controlled via PWM to regulate motor speed and direction, and a disable pin for enabling/disabling the motor.

Note

The motor drivers operate at a fixed PWM frequency of 5 kHz, which provides a good balance between motor performance and switching losses.

Characteristics

DC motor driver specifications
Parameter	Value	Remark
Number of motors	4	Independent control
Power supply voltage	9-30V DC	Same as module supply
PWM frequency	5 kHz	Fixed
PWM resolution	13 bits	8192 steps
Direction control	Bidirectional	Forward/Reverse
Current monitoring	Yes	Per motor channel

Code examples

The example code below demonstrates how to control a DC motor with the OI-Dc module:

/**
 * @file DcMotorSimple.cpp 
 * @author Georges de Massol
 * @brief Simple example for OI-DC (DC Motor Controller) module
 * 
 * This example demonstrates basic motor control with the OpenIndus DC module:
 * - Run motor forward at full speed
 * - Measure current
 * - Run motor backward at full speed
 * - Measure current
 * - Stop motor
 * - Measure current (should be near 0A)
 * Hardware Wiring Diagram:
 * 
 *     OI-DC Module Pinout & Test Configuration
 *     =========================================
 * 
 *     Power Supply (24V)   
 *          +                                                         +----------------
 *          |                                                         |               |
 *          |                                                         |               |
 *     +----|-------------------------+-------+--------------+--------+----+          |
 *     |    |        |       |        |       |      |       |        |    |          |
 *     |  9V-30V   9V-30V   /B2      /A2      |     /B1     /A1       |    |        _____
 *     |   VIN      VIN     DIN4    HB4_2   HB3_2   DIN2   HB2_2   HB1_2   |       /     \
 *     |                                                                   |      |   M   |
 *     |                                                                   |       \_____/       
 *     |   GND      GND     DIN3    HB4_1   HB3_1   DIN1   HB2_1   HB1_1   |          |
 *     |    |        |       B2       A2      |      B1      A1       |    |          |
 *     |    |        |       |        |       |      |       |        |    |          |
 *     +----+-------------------------+-------+--------------+--------+----+          |
 *          |                                                         |               |
 *          |                                                         |               |
 *          -                                                         +----------------
 *         GND
 * 
 * @date November 2025
 */

#include "OpenIndus.h"
#include "Arduino.h"

Dc dc;  // Create DC motor controller object

static const char TAG[] = "Main";

void setup(void)
{
}

void loop(void)
{
    float current;
    
    // 1. Run motor forward at 100% speed
    dc.run(MOTOR_1, FORWARD, 100);
    current = dc.getCurrent(MOTOR_1);
    ESP_LOGI(TAG, "MOTOR_1 FORWARD: Current = %.3f A", current);
    
    delay(2000);  // Run for 2 seconds
    
    // 2. Run motor backward at 100% speed
    dc.run(MOTOR_1, REVERSE, 100);
    current = dc.getCurrent(MOTOR_1);
    ESP_LOGI(TAG, "MOTOR_1 REVERSE: Current = %.3f A", current);
    
    delay(2000);  // Run for 2 seconds
    
    // 3. Stop motor
    dc.stop(MOTOR_1);
    current = dc.getCurrent(MOTOR_1);
    ESP_LOGI(TAG, "MOTOR_1 STOPPED: Current = %.3f A", current);
    // Nothing to do in loop
    delay(2000);
}

This example demonstrates basic motor control operations:

Starting a motor: Use run() with motor number, direction (FORWARD/REVERSE), and duty cycle (0-100%).
Reading current: Use getCurrent() to monitor motor load.
Stopping a motor: Use stop() to disable the motor driver.

Note

The duty cycle parameter in the run() function represents the percentage of maximum speed. A value of 100% corresponds to full speed, while 0% effectively stops the motor (though using stop() is preferred for this purpose).

Software API

class MotorDc : public Motor

DC Motor control class.

Public Static Functions

static void run(MotorNum_t motor, MotorDirection_t direction, float dutyCycle)

Run a DC motor with specified direction and duty cycle.

Parameters:

motor – Motor number
direction – Motor direction (FORWARD/REVERSE)
dutyCycle – Duty cycle percentage (0..100)

static void stop(MotorNum_t motor)

Stop a DC motor.

Parameters:: motor – Motor number

static void brake(MotorNum_t motor)

Brake a DC motor by calling run with speed 0.

Parameters:: motor – Motor number

static float getCurrent(MotorNum_t motor)

Get current consumption of a DC motor.

Parameters:: motor – Motor number
Returns:: float current in A

static uint8_t getFault(MotorNum_t motor)

Get the current fault status from DRV8873 for a specific motor.

Parameters:: motor – Motor number (0-3)
Returns:: uint8_t Fault status register value (0 if no fault)

static esp_err_t clearFault(MotorNum_t motor)

Clear all faults in DRV8873 for a specific motor.

Parameters:: motor – Motor number (0-3)
Returns:: esp_err_t ESP_OK on success, error code otherwise

static esp_err_t setMode(drv8873_mode_t mode, MotorNum_t motor)

Set the control mode of DRV8873 for a specific motor.

Parameters:

mode – Control mode to set (PH/EN, PWM, Independent, Disabled)
motor – Motor number (0-3)

Returns:

esp_err_t ESP_OK on success, error code otherwise