Diff: ping.h

Revision:

3:0c337c262d84

Parent:

1:72fbcb01291d

Child:

4:ddffe9339bb1

--- a/ping.h	Sun Jul 27 19:55:41 2014 +0000
+++ b/ping.h	Mon Jul 28 00:16:34 2014 +0000
@@ -4,7 +4,9 @@
 #include "mbed.h"
 #include "FPointer.h"
 
-#define MEASUREMENT_DELAY_US    200
+#define MEASUREMENT_DELAY_US        200
+#define SPEED_OF_SOUND_CM_PER_US    0.034029
+#define SPEED_OF_SOUND_IN_PER_US    0.0133972441
 
 /**
  * Class for interfacing with the Parallax Ping))) Ultrasonic Sensor
@@ -56,6 +58,22 @@
         uint32_t getRawReading() { return mRawReading; }
         
         /**
+         * Gets the distance sound can travel, in centimeters, for a given time in uS.
+         *
+         * @param time_us Time traveled in microseconds.
+         * @return The distance traveled in centimeters.
+         */
+        float getDistanceCm(uint32_t time_us) { return time_us * SPEED_OF_SOUND_CM_PER_US; }
+        
+        /**
+         * Gets the distance sound can travel, in inches, for a given time in uS.
+         *
+         * @param time_us Time traveled in microseconds.
+         * @return The distance traveled in inches.
+         */
+        float getDistanceIn(uint32_t time_us) { return time_us * SPEED_OF_SOUND_IN_PER_US; }
+        
+        /**
          * Attach a callback function that will be called when a valid reading is available.
          *
          * @param function Function pointer for callback.
@@ -79,7 +97,6 @@
         bool mValid;
         bool mContinuous;
         
-        uint32_t mStartTime;
         Timer mTimer;
         Ticker mMeasureDelayTicker;