00001 /* mbed R/C Servo
00002  * Copyright (c) 2007-2009 sford, cstyles
00003  * Released under the MIT License: http://mbed.org/license/mit
00004  */
00005   
00006 #ifndef MBED_SERVO_H
00007 #define MBED_SERVO_H
00008 
00009 #include "mbed.h"
00010 
00011 /* Class: Servo
00012  *  Abstraction on top of PwmOut to control the position of a servo motor
00013  *
00014  * Example:
00015  * > // Continuously sweep the servo through it's full range
00016  * > #include "mbed.h"
00017  * > #include "Servo.h"
00018  * >
00019  * > Servo myservo(p21);
00020  * >
00021  * > int main() {
00022  * >     while(1) {
00023  * >         for(int i=0; i<100; i++) {
00024  * >             myservo = i/100.0;
00025  * >             wait(0.01);
00026  * >         }
00027  * >         for(int i=100; i>0; i--) {
00028  * >             myservo = i/100.0;
00029  * >             wait(0.01);
00030  * >         }
00031  * >     }
00032  * > }
00033  */
00034 class Servo {
00035 
00036 public:
00037     /* Constructor: Servo
00038      *  Create a servo object connected to the specified PwmOut pin
00039      *
00040      * Variables:
00041      *  pin - PwmOut pin to connect to 
00042      */
00043     Servo(PinName pin);
00044     
00045     /* Function: write
00046      *  Set the servo position, normalised to it's full range
00047      *
00048      * Variables:
00049      *  percent - A normalised number 0.0-1.0 to represent the full range.
00050      */
00051     void write(float percent);
00052     
00053     /* Function: read
00054      *  Read the servo motors current position
00055      *
00056      * Variables:
00057      *  returns - A normalised number 0.0-1.0  representing the full range.
00058      */
00059     float read();
00060     
00061     /* Function: position
00062      *  Set the servo position
00063      *
00064      * Variables:
00065      *  degrees - Servo position in degrees
00066      */
00067     void position(float degrees);
00068     
00069     /* Function: calibrate
00070      *  Allows calibration of the range and angles for a particular servo
00071      *
00072      *
00073      * Variables:
00074      *  range - Pulsewidth range from center (1.5ms) to maximum/minimum position in seconds
00075      *  degrees - Angle from centre to maximum/minimum position in degrees
00076      */
00077     void calibrate(float range = 0.0005, float degrees = 45.0); 
00078         
00079     /* Function: operator=
00080      *  Shorthand for the write and read functions
00081      */
00082     Servo& operator= (float percent);
00083     Servo& operator= (Servo& rhs);
00084     operator float();
00085 
00086 protected:
00087     PwmOut _pwm;
00088     float _range;
00089     float _degrees;
00090     float _p;
00091 };
00092 
00093 
00094 
00095 #endif