Arduino and Servo motors

Arduino has a Servo library which allows to control servo motors. Today we will use the following small servo motor and write a program, which read a angle value from Serial port and rotate servo motor according to it.

This is the source code of program

	#include <Servo.h>
	// make sure the pin has PWM capability
	const int servo_pin = 11;
	Servo myservo;
	void setup()
	{
	Serial.begin(9600);
	myservo.attach(servo_pin);
	}
	void loop()
	{
	while (0 < Serial.available())
	{
	int pos = 0;
	// Read number from Serial port
	int b = -1;
	while (-1 != (b = Serial.read()))
	{
	if (b > '9' || b < '0')
	{
	pos = 0;
	Serial.println("Invalid number");
	break;
	}
	pos = 10 * pos + (b - '0');
	}
	// Check is number in [0,180)
	if ((0 <= pos) && (pos < 180)) {
	Serial.println(pos, DEC);
	myservo.write(pos);
	} else {
	Serial.println("Enter number in [0,180)");
	}
	}
	delay(100);
	}

view raw servo.pde hosted with ❤ by GitHub

Compile and upload above code to Arduino, then connect control pin(gray wire) of Servo motor to Arduino pin 11, connect black wire to Gnd of Arduino and red wire to +5V. This is how it looks:

And this is a video demonstration of moving Servo 0 -> 90 -> 180 -> 0 -> 90: