Introduction

This tutorial explores controlling a linear actuator with an Arduino, a versatile method for achieving controlled linear motion in electromechanical projects. Linear actuators convert rotational motion into linear displacement, making them ideal for tasks like lifting, pushing, or adjusting positions in automation and robotics. In this experiment, you’ll learn how to connect a linear actuator to an Arduino using a motor driver or relay module, program it to extend and retract, and test its performance. This guide is perfect for enthusiasts and engineers looking to integrate linear motion into their designs.

Linear actuators typically operate on DC voltage (e.g., 12V) and can be controlled by reversing polarity to change direction. By using an Arduino with an H-Bridge or relay setup, you’ll gain precise control over the actuator’s movement, which we’ll demonstrate in this hands-on setup.

Components Required

To control a linear actuator with Arduino, you’ll need the following components:

• Microcontroller (e.g., Arduino Uno): Sends control signals to manage the actuator’s direction and movement.
• Linear Actuator (e.g., 12V DC): A DC-powered actuator with a stroke length suited to your project (e.g., 100mm).
• H-Bridge Module (e.g., L298N) or Relay Module: Controls the actuator’s direction by switching voltage polarity.
• Power Supply (e.g., 12V, 2A): Provides sufficient voltage and current for the actuator, separate from the Arduino’s power.
• Connecting Wires: Jumper wires for secure electrical connections.
• Breadboard or PCB: For prototyping the circuit.
• Optional: Limit Switches: Prevents over-extension or retraction by signaling end positions.

Schematic

The schematic outlines how to wire the linear actuator to the Arduino via an H-Bridge module for directional control:

Basic connection overview: - Connect the linear actuator’s two wires to the H-Bridge output terminals (e.g., OUT1 and OUT2 on L298N). - Wire the H-Bridge input pins (e.g., IN1 and IN2) to Arduino digital pins (e.g., D9 and D10, PWM-capable). - Attach the power supply (e.g., 12V) to the H-Bridge’s VCC and GND, ensuring a common ground with the Arduino. - If using limit switches, connect them to Arduino digital pins (e.g., D2 and D3) and GND for feedback.

Note: Check your actuator’s voltage and current ratings (e.g., 12V, 1A) and ensure the H-Bridge or relay can handle the load. Use a heat sink on the H-Bridge if needed.

Steps

Follow these steps to set up and test your linear actuator control system:

1. Assemble the Circuit: Connect the linear actuator to the H-Bridge outputs (OUT1, OUT2) and wire the H-Bridge inputs (IN1, IN2) to Arduino D9 and D10.
2. Power Connections: Attach a 12V power supply to the H-Bridge VCC and GND, and power the Arduino via USB, sharing a common GND.
3. Upload the Code: Load the Arduino sketch (see "Code Example" below) to control the actuator’s extension and retraction.
4. Test Extension: Run the code to extend the actuator fully and verify smooth motion.
5. Test Retraction: Reverse the direction to retract the actuator, checking for consistent operation.
6. Add Limits (Optional): Integrate limit switches and modify the code to stop the actuator at its endpoints.

Code Example

Below is an Arduino sketch to control a linear actuator’s extension and retraction using an H-Bridge (e.g., L298N):

                
// Define H-Bridge control pins
const int IN1 = 9;  // PWM-capable pin
const int IN2 = 10; // PWM-capable pin

void setup() {
    pinMode(IN1, OUTPUT);
    pinMode(IN2, OUTPUT);
    Serial.begin(9600);  // For debugging
}

void extendActuator() {
    Serial.println("Extending actuator");
    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    delay(5000);  // Run for 5 seconds (adjust based on actuator speed)
    stopActuator();
}

void retractActuator() {
    Serial.println("Retracting actuator");
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, HIGH);
    delay(5000);  // Run for 5 seconds
    stopActuator();
}

void stopActuator() {
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
}

void loop() {
    extendActuator();
    delay(2000);  // Pause for 2 seconds
    retractActuator();
    delay(2000);  // Pause for 2 seconds
}
                
            

This code extends the actuator for 5 seconds, stops, then retracts it for 5 seconds, repeating indefinitely. Adjust the `delay()` values based on your actuator’s stroke time.

Applications

Controlling a linear actuator with Arduino has numerous practical applications, including:

• Automation Systems: Adjusts positions in conveyor systems or automated doors.
• Prototyping for Robotics: Drives linear motion in robotic grippers or legs.
• Educational Experiments: Teaches actuator control and polarity switching.
• Home Automation: Operates adjustable furniture (e.g., standing desks) or window openers.
• Agricultural Tech: Controls valves or levers in automated farming equipment.