DRV8825: High-Performance Stepper Motor Driver Explained

The DRV8825 is a high-power stepper motor driver module widely used in 3D printers, CNC machines, and robotics. It provides precise control over stepper motors and supports microstepping, allowing for smooth and accurate movement.

🔹 1. What is the DRV8825?

• The DRV8825 is a bipolar stepper motor driver that can drive NEMA 17 and NEMA 23 stepper motors.
• It is more powerful than the A4988, offering higher current handling and microstepping precision.
• Works with Arduino, Raspberry Pi, ESP32, and other microcontrollers.

📌 Key Features:

• Motor Voltage: 8.2V – 45V
• Logic Voltage: 3.3V / 5V (Arduino Compatible)
• Max Current: 2.5A per coil (with cooling)
• Microstepping Support: 1, 1/2, 1/4, 1/8, 1/16, 1/32 steps
• Thermal & Overcurrent Protection

🔹 2. DRV8825 Pinout & Functions

The DRV8825 module has 16 pins for motor control and microstepping configuration.

📌 Important:

• VMOT must be connected to motor power (e.g., 12V, 24V).
• Microstepping (MS1, MS2, MS3) determines step resolution.
• STEP & DIR control motor speed and direction.

🔹 3. How DRV8825 Works

• The DRV8825 receives signals from the microcontroller to move the stepper motor one step at a time.
• Pulse on STEP pin → Moves motor one step.
• DIR pin controls direction (HIGH = Clockwise, LOW = Counterclockwise).
• Microstepping reduces vibrations and provides precise motor control.

📌 Microstepping Settings (MS1, MS2, MS3 Pins)

🔹 4. Connecting DRV8825 to Arduino

🛠 Required Components

• 1x Arduino (Uno, Mega, etc.)
• 1x DRV8825 Stepper Motor Driver
• 1x NEMA 17 Stepper Motor
• 1x 12V or 24V Power Supply
• 1x 100µF Capacitor (Prevents Voltage Spikes)
• Jumper Wires

🛠 Wiring

📌 Always connect a 100µF capacitor across VMOT & GND to prevent voltage spikes.

🔹 5. Arduino Code for Controlling a Stepper Motor

#define STEP_PIN 9
#define DIR_PIN 8

void setup() {
    pinMode(STEP_PIN, OUTPUT);
    pinMode(DIR_PIN, OUTPUT);
}

void loop() {
    digitalWrite(DIR_PIN, HIGH); // Set Direction (Clockwise)
    
    for (int i = 0; i < 200; i++) {  // Move 1 full revolution (200 steps)
        digitalWrite(STEP_PIN, HIGH);
        delayMicroseconds(500);  // Control Speed
        digitalWrite(STEP_PIN, LOW);
        delayMicroseconds(500);
    }
    
    delay(1000); // Pause

    digitalWrite(DIR_PIN, LOW); // Change Direction (Counterclockwise)
    
    for (int i = 0; i < 200; i++) {
        digitalWrite(STEP_PIN, HIGH);
        delayMicroseconds(500);
        digitalWrite(STEP_PIN, LOW);
        delayMicroseconds(500);
    }
    
    delay(1000);
}

📌 What happens?

• The motor rotates 1 full revolution clockwise.
• Pauses for 1 second.
• Then rotates 1 full revolution counterclockwise.

🔹 6. Adjusting DRV8825 Current Limit

To prevent motor overheating or overcurrent damage, the current limit must be set correctly.

✅ Formula for Current Limit

• VREF = Reference Voltage (Measure with Multimeter on VREF Pin)
• Max Current = 2.5A (With Heatsink)
• Set VREF between 0.5V – 1.2V

📌 To Adjust Current:

1. Measure VREF using a multimeter (Touch the small potentiometer on DRV8825).
2. Turn the potentiometer clockwise to increase, counterclockwise to decrease.
3. For NEMA 17 stepper motors (1.5A max), set VREF to ~0.75V.

🔹 7. Applications of DRV8825

✅ 3D Printers – Controls precise motor movements.
✅ CNC Machines – Used for stepper motor control.
✅ Robotics – Drives robotic arms, wheels, and actuators.
✅ Automated Systems – Used in conveyor belts, automation.
✅ DIY Motorized Projects – Any project requiring high-precision motor control.

🔹 8. DRV8825 vs Other Stepper Drivers

📌 Verdict:

• DRV8825 is better than A4988 for higher power motors.
• TMC2209 is best for silent operation.

🎯 Conclusion

• The DRV8825 is a high-performance stepper motor driver with 1/32 microstepping.
• Handles up to 2.5A per coil, making it stronger than A4988.
• Used in 3D printers, CNC machines, and robotic applications.
• Supports PWM control, direction control, and current adjustment.