Example Code for Arduino-Standard PWM DC control

This article offers a comprehensive guide on using Arduino for Standard PWM DC motor control, including hardware and software preparation, wiring diagrams, and sample code that allows users to control robot movements such as moving forward, backward, turning left, and right. It also includes troubleshooting tips for ensuring accurate motor direction and speed control. Ideal for hobbyists and professionals seeking to improve their robotics projects with Arduino.

Hardware Preparation

4WD Mobile Platform (Arduino Controller Supported), ROB0003, 1, DFRobot
Romeo-All in one Controller, DFR0225, 1, Romeo
DF05BB Standard Servo (5kg), SER0020, 1, DFRobot
IR Kit For Arduino, DFR0107, 1, DFRobot
10 sets M3 * 10 hexagonal standoffs mounting kit, FIT0063, 1, DFRobot
URM ultrasound mounting bracket, FIT0006, 1, DFRobot
URM37 V4.0 Ultrasonic Sensor, SEN0001, 1, DFRobot
Adjustable Infrared Sensor Switch, SEN0019, 3, DFRobot
Light Disc with 7 SMD RGB LED, DFR0106, 2, DFRobot
DFRobot Bluetooth V3, TEL0026, 1, DFRobot
Pan and Tilt Kit (Black Anodized) (no servos), FIT0004, 1, DFRobot
Wire cutter and wire stripper, 1, -
Soldering Iron, 1, -
Solder, 1, -
Phillips Screw Driver, 1, -
Pliers, 1, -
5xAA batteries (1.2V rechargeable or 1.5V alkaline), 1 set, -

Software Preparation

Arduino IDE (download from Arduino)

Wiring Diagram

Connect the motors to M1 (left) and M2 (right):

Other wiring matches the Bluetooth Remote Control section.

Other Preparation Work

Connect the robot to your computer via USB.
Set the Arduino IDE's Serial Monitor baud rate to 19200.
Ensure the motors are wired correctly (flip wiring if motors move in the wrong direction).

Sample Code

int E1 = 5; //M1 Speed Control
int E2 = 6; //M2 Speed Control
int M1 = 4; //M1 Direction Control
int M2 = 7; //M1 Direction Control

///For previous Romeo, please use these pins.

//int E1 = 6; //M1 Speed Control
//int E2 = 9; //M2 Speed Control
//int M1 = 7; //M1 Direction Control
//int M2 = 8; //M1 Direction Control

void stop(void) //Stop
{
digitalWrite(E1,LOW);
digitalWrite(E2,LOW);
}

void advance(char a,char b) //Move forward
{
analogWrite (E1,a); //PWM Speed Control
digitalWrite(M1,HIGH);
analogWrite (E2,b);
digitalWrite(M2,HIGH);
}

void back_off (char a,char b) //Move backward
{analogWrite (E1,a);
digitalWrite(M1,LOW);
analogWrite (E2,b);
digitalWrite(M2,LOW);
}

void turn_L (char a,char b) //Turn Left
{
analogWrite (E1,a);
digitalWrite(M1,LOW);
analogWrite (E2,b);
digitalWrite(M2,HIGH);
}

void turn_R (char a,char b) //Turn Right
{
analogWrite (E1,a);
digitalWrite(M1,HIGH);
analogWrite (E2,b);
digitalWrite(M2,LOW);
}


void setup(void)
{
    int i;
    for(i=6;i<=9;i++)
    pinMode(i, OUTPUT);
    Serial.begin(19200); //Set Baud Rate
}

void loop(void)
{
    char val = Serial.read();
    if(val!=-1)
    {
        switch(val)
        {
            case 'w'://Move Forward
            advance (100,100); //PWM Speed Control
            break;

            case 's'://Move Backward
            back_off (100,100);
            break;

            case 'a'://Turn Left
            turn_L (100,100);
            break;

            case 'd'://Turn Right
            turn_R (100,100);
            break;
        }
        delay(40);
    }
    else stop();
}

Result

Send "w" via Serial Monitor to move forward.
Send "s" to move backward.
Send "a" to turn left.
Send "d" to turn right.
Stop sending commands to halt the robot.

Additional Information

Adjust the PWM values (e.g., advance(100,100)) to change the robot's speed.
For older Romeo controllers, uncomment the alternate pin definitions in the code.