Servo Motor
Servo Motor
This library allows you to control RC (hobby) servo motors. Servos have integrated gears and a shaft that can be precisely controlled. Standard servos allow the shaft to be positioned at various angles, usually between 0 and 180 degrees. Continuous rotation servos allow the rotation of the shaft to be set to various speeds. To use, specify #include <servo.h>. You will need to create Servo myservo or a similar instance.
attach
- Description
- Initializes and attaches the Servo output to a pin.
- Syntax
- servo.attach(int pin)servo.attach(int pin, int min, int max)
- Parameters
- pin: The number of the pin to which the servo is attached
min: The pulse width, in microseconds, corresponding to the minimum (0-degree) angle on the servo (defaults to 544)
max: The pulse width, in microseconds, corresponding to the maximum (180-degree) angle on the servo (defaults to 2400). - Returns
- None
write
- Description
- Writes a value to the servo to set the shaft angle, controlling the shaft accordingly. The pulse for moving the shaft to that orientation is output from the pin specified in attach.
- Syntax
- servo.write(int angle)
- Parameters
- angle: The value of the angle to write to the servo, from 0 to 180
- Returns
- None
writeMicroseconds
- Description
- Writes a value in microseconds (uS) to the servo, controlling the shaft accordingly. On a standard servo, this will set the angle of the shaft. On standard servos a parameter value of 1000 is fully counter-clockwise, 2000 is fully clockwise, and 1500 is in the middle.
- Syntax
- servo.writeMicroseconds(int us)
- Parameters
- us: The value of the pulse width in microseconds.
- Returns
- None
read
- Description
- Read the current angle of the servo.
- Syntax
- int servo.read()
- Parameters
- None
- Returns
- pulse width [us]
attached
- Description
- Check whether the servo variable is attached to a pin.
- Syntax
- bool servo.attached()
- Parameters
- None
- Returns
- True if the servo is attached to pin; false otherwise.
detach
- Description
- Detach the servo variable from its pin. This stops the pulse width output from the specified pin.
- Syntax
- servo.detach()
- Parameters
- None
- Returns
- None
Sample Program
This sample uses pin 9 as the servo motor output pin, enabling the motor to be run by pushing a switch on the GR-PEACH board.
#include <Arduino.h>
#include <servo.h>
#define INTERVAL 50
char g_inc = 10;
unsigned char g_pos = 0;
Servo servo0;
void setup()
{
pinMode(PIN_SW, INPUT);
servo0.attach(9);
servo0.write(g_pos);
}
void loop() {
if(digitalRead(PIN_SW) == LOW){
g_pos = g_pos + g_inc;
servo0.write(g_pos);
if(g_pos == 180 | g_pos == 0){
g_inc = g_inc * -1;
}
}
delay(INTERVAL);
}