Output a pulse width modulated signal on a Servo Motor.
The Micro Servo Motor
can rotate 180 degrees and is usually used in applications
such as robotics, CNC machinery, or automated manufacturing.
By using the'analogWrite function [analogWrite(pin, value, [freq], [callback]),
the BeagleBone will send Pulse Width Modulated Signals to control the Servo Motor.
The position of the servo motor is set by the length of a pulse.
In the following program, the frequency is set at 60Hz, which means that the
servo receives a pulse every 16.66ms. The length of the pulse, or the duty cycle,
can be changed from 3% to 14.5% and can be changed to rotate the servo motor.
The example below, when run, will adjust the position of the servo motor between its two extremes repeatitively.
More information regarding PWMs can be found on the Wikipedia pulse-width modulation page.
- Connect the pins as follows:
| Servo | Pin | Bone | |
|---|---|---|---|
| GND | GND | P9_1 | P2_15 |
| V+ | 3.3V | P9_3 | P1_14 |
| PWM | PWM via 1kOhm resistor | P9_14 | P1_36 |
- Connect a 1kohm resistor to the "PWM" pin of the Servo Motor and to P9_14 of the board.
- Click "Run" on the code. The value of 'position' will go between 0 and 1 changing by 'increment' amount with updates every 200ms.