Servomotors

A servomotor (or servo motor or simply servo) is a rotary or linear actuator that allows for precise control angular or linear position, velocity, and acceleration in a mechanical system. It constitutes part of a servomechanism, and consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors.

How Servos Work

• A servo motor moves to a specific position based on a control signal (usually a Pulse Width Modulation or PWM signal).
• The control signal determines the angle, typically between 0° to 180° for most hobby servos.

Wiring the Servo to an Arduino

1. Connect the Servo Wires:

   • Red wire (VCC): Connect to the 5V pin on the Arduino.
   • Brown/Black wire (GND): Connect to the GND pin on the Arduino.
   • Orange/White wire (Signal): Connect to a PWM pin on the Arduino (e.g., Pin 9).

2. Optional External Power Source:

   • If your servo draws more current than the Arduino can provide, use an external 5V power source and connect its ground to the Arduino’s ground.

Arduino Code:

#include <Servo.h>  // Include the Servo library

Servo myServo;      // Create a Servo object
int servoPin = 9;   // PWM pin connected to the servo
int pos = 0;        // Variable to store servo position

void setup() {
  myServo.attach(servoPin);  // Attach the servo to the pin
}

void loop() {
  // Sweep from 0° to 180°
  for (pos = 0; pos <= 180; pos += 1) {
    myServo.write(pos);  // Move the servo to the specified position
    delay(15);           // Wait for the servo to reach the position
  }

  // Sweep from 180° to 0°
  for (pos = 180; pos >= 0; pos -= 1) {
    myServo.write(pos);  // Move the servo to the specified position
    delay(15);
  }
}

Tips and Best Practices

1. Use Proper Voltage:
   • Check the servo’s datasheet for voltage requirements (usually 4.8V–6V).
2. Avoid Overloading:
   • Do not use the Arduino’s 5V pin for large or multiple servos.
3. Add Capacitors:
   • If using an external power source, add a capacitor (e.g., 100µF) across the power lines to stabilize voltage.
4. Test and Calibrate:
   • Test the servo’s range to ensure it doesn’t exceed physical limits and cause damage.
5. Use External Power for Heavy Loads:
   • If the servo becomes unresponsive or jittery, it might need more power.

Tutorials

• Gettings started with servos and Arduino