Diff: sonar.h

Revision:

0:7e65f5077f5a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sonar.h	Wed Nov 21 20:47:05 2012 +0000
@@ -0,0 +1,42 @@
+#include "mbed.h"
+/*** @file Driver for Maxbotix sonar modules
+ * Uses pulse width input to read range results.
+ * @author Daniel Casner <http://www.danielcasner.org>
+ *
+ * Known Issues:
+ * If a timer rollover occures during a sample, the driver will drop that sample.
+ */
+ 
+ /** Object representation of a sonar instance
+  */
+ class Sonar {
+ public:
+    /** Sets up the driver and starts taking measurements
+     * @param input The pin to read pulses from
+     * @param t A running timer instance used to measure pulse width.
+     * Note that the timer must have been started or results will be
+     * invalid.
+     */
+    Sonar(PinName input, Timer& t);
+    
+    /// Returns range in cm as int
+    int read();
+    
+    /// Returns the range in CM as an int
+    operator int();
+    
+ private:
+    /// Inturrupt at start of pulse
+    void pulseStart();
+    /// Interrupt at end of pulse
+    void pulseStop();
+    
+    /// Interrupt driver for the input pin
+    InterruptIn interrupt;
+    /// Reference to global timer instance
+    Timer& time;
+    /// Time of the start of the current pulse
+    int pulseStartTime;
+    /// The most recent sample
+    int range;
+ };
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