Revision 0:24148c673250, committed 2009-11-16

Comitter:

simon

Date:

Mon Nov 16 18:24:16 2009 +0000

Child:

1:92f46d402550

Commit message:

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Servo.cpp	Mon Nov 16 18:24:16 2009 +0000
@@ -0,0 +1,56 @@
+/* mbed R/C Servo
+ * Copyright (c) 2007-2009 sford, cstyles
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#include "Servo.h"
+#include "mbed.h"
+
+static float clamp(float value, float min, float max) {
+    if(value < min) {
+        return min;
+    } else if(value > max) {
+        return max;
+    } else {
+        return value;
+    }
+}
+
+Servo::Servo(PinName pin) : _pwm(pin) {
+    calibrate();
+    write(0.5);
+}
+
+void Servo::write(float percent) {
+    float offset = _range * 2.0 * (percent - 0.5);
+    _pwm.pulsewidth(0.0015 + clamp(offset, -_range, _range));
+    _p = clamp(percent, 0.0, 1.0);
+}
+
+void Servo::position(float degrees) {
+    float offset = _range * (degrees / _degrees);
+    _pwm.pulsewidth(0.0015 + clamp(offset, -_range, _range));
+}
+
+void Servo::calibrate(float range, float degrees) {
+    _range = range;
+    _degrees = degrees;
+}
+
+float Servo::read() {
+    return _p;
+}
+
+Servo& Servo::operator= (float percent) { 
+    write(percent);
+    return *this;
+}
+
+Servo& Servo::operator= (Servo& rhs) {
+    write(rhs.read());
+    return *this;
+}
+
+Servo::operator float() {
+    return read();
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Servo.h	Mon Nov 16 18:24:16 2009 +0000
@@ -0,0 +1,95 @@
+/* mbed R/C Servo
+ * Copyright (c) 2007-2009 sford, cstyles
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+  
+#ifndef MBED_SERVO_H
+#define MBED_SERVO_H
+
+#include "mbed.h"
+
+/* Class: Servo
+ *  Abstraction on top of PwmOut to control the position of a servo motor
+ *
+ * Example:
+ * > // Continuously sweep the servo through it's full range
+ * > #include "mbed.h"
+ * > #include "Servo.h"
+ * >
+ * > Servo myservo(p21);
+ * >
+ * > int main() {
+ * >     while(1) {
+ * >         for(int i=0; i<100; i++) {
+ * >             myservo = i/100.0;
+ * >             wait(0.01);
+ * >         }
+ * >         for(int i=100; i>0; i--) {
+ * >             myservo = i/100.0;
+ * >             wait(0.01);
+ * >         }
+ * >     }
+ * > }
+ */
+class Servo {
+
+public:
+    /* Constructor: Servo
+     *  Create a servo object connected to the specified PwmOut pin
+     *
+     * Variables:
+     *  pin - PwmOut pin to connect to 
+     */
+    Servo(PinName pin);
+    
+    /* Function: write
+     *  Set the servo position, normalised to it's full range
+     *
+     * Variables:
+     *  percent - A normalised number 0.0-1.0 to represent the full range.
+     */
+    void write(float percent);
+    
+    /* Function: read
+     *  Read the servo motors current position
+     *
+     * Variables:
+     *  returns - A normalised number 0.0-1.0  representing the full range.
+     */
+    float read();
+    
+    /* Function: position
+     *  Set the servo position
+     *
+     * Variables:
+     *  degrees - Servo position in degrees
+     */
+    void position(float degrees);
+    
+    /* Function: calibrate
+     *  Allows calibration of the range and angles for a particular servo
+     *
+     *
+     * Variables:
+     *  range - Pulsewidth range from center (1.5ms) to maximum/minimum position in seconds
+     *  degrees - Angle from centre to maximum/minimum position in degrees
+     */
+    void calibrate(float range = 0.0005, float degrees = 45.0); 
+        
+    /* Function: operator=
+     *  Shorthand for the write and read functions
+     */
+    Servo& operator= (float percent);
+    Servo& operator= (Servo& rhs);
+    operator float();
+
+protected:
+    PwmOut _pwm;
+    float _range;
+    float _degrees;
+    float _p;
+};
+
+
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Nov 16 18:24:16 2009 +0000
@@ -0,0 +1,27 @@
+#include "mbed.h"
+#include "Servo.h"
+
+Servo myservo(p21);
+Serial pc(USBTX, USBRX);
+
+int main() {
+    printf("Servo Calibration Controls:\n");
+    printf("1,2,3 - Position Servo (full left, middle, full right)\n");
+    printf("4,5 - Decrease or Increase range\n");
+
+    float range = 0.0005;
+    float position = 0.5;
+    
+    while(1) {                   
+        switch(pc.getc()) {
+            case '1': position = 0.0; break;
+            case '2': position = 0.5; break;
+            case '3': position = 1.0; break;
+            case '4': range += 0.0001; break; 
+            case '5': range -= 0.0001; break; 
+        }
+        printf("position = %.1f, range = +/-%0.4f\n", position, range);
+        myservo.calibrate(range, 45.0); 
+        myservo = position;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Nov 16 18:24:16 2009 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479