Getting started with servo motors

Servo motor basics

In this part of the lab, get started with a single continuous Servo motor by following the steps below.

1. Copy sketch from below

2. Upload sketch

3. Unplug USB

4. Plug in servo wires (red -> 5V, black -> GND, white -> pin 9)

5. Plug in battery supply

6. Check that your servo rotates counter clockwise for 2 seconds, then clockwise for 2 seconds, then stops for 2 seconds (and repeats this sequence).

Important - manage your power supply! 

NEVER attach both power supplies to the Arduino -- you should have the USB cable or the DC jack or neither!

Any time you want to change your sketch, follow the sequence below.

DO NOT PLUG IN THE USB cable to the computer until told to do so!

1. unplug your battery supply

2. unplug your VCC (5V) and GND wires

   1. plug in your USB cable to the computer

   2. upload your sketch

   3. unplug your USB cable

   4. plug in your VCC (5V) and GND wires

   5. plug in your battery supply

Arduino sketch

The stop value seems to differ slightly among each servo motor part. You will have to figure out the right number for your specific servo motor. When you do, write it on a piece of masking tape and attach it to your motor.

Update: there is a little calibration dial (yellow). To calibrate, run the following sketch and rotate until the motor stops turning.

#include <Servo.h>

Servo myServo;

void setup() { 

  myServo.attach(9);

  myServo.writeMicroseconds(1500);  // Stop 

} 

void loop() { } 

Once you've calibrated, use the following sketch to get started with the motor.

/**

 * Basic code to test Parallax continuous rotation servo

 * From http://learn.parallax.com/KickStart/900-00008

 **/

#include <Servo.h>

Servo myServo;        // Create Servo object to control the servo 

int stopValue = 1500; // this may differ depending on your motor

void setup() 

{ 

  myServo.attach(9);  // Servo is connected to digital pin 9 

} 

void loop() 

{ 

  myServo.writeMicroseconds(1700);  // Counter clockwise

  delay(2000);                      // Wait 2 seconds

  myServo.writeMicroseconds(1300);  // Clockwise

  delay(2000);

  myServo.writeMicroseconds(stopValue);  // Stop

  delay(2000); 

}