Daniel Casner / MaxbotixDriver

A driver library for Maxbotix / Maxsonar sonar range finders that uses the pulse width output function to achieve better accuracy with less load on the mbed processor.

Dependents:   QuadCopter mbed-IBooth-ETH

sonar.h@0:7e65f5077f5a, 2012-11-21 (annotated)

Committer:
DanielC
Date:
Wed Nov 21 20:47:05 2012 +0000
Revision:
0:7e65f5077f5a
Initial commit of probably working but untested sonar driver library.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
DanielC 0:7e65f5077f5a 1 #include "mbed.h"
DanielC 0:7e65f5077f5a 2 /*** @file Driver for Maxbotix sonar modules
DanielC 0:7e65f5077f5a 3 * Uses pulse width input to read range results.
DanielC 0:7e65f5077f5a 4 * @author Daniel Casner <http://www.danielcasner.org>
DanielC 0:7e65f5077f5a 5 *
DanielC 0:7e65f5077f5a 6 * Known Issues:
DanielC 0:7e65f5077f5a 7 * If a timer rollover occures during a sample, the driver will drop that sample.
DanielC 0:7e65f5077f5a 8 */
DanielC 0:7e65f5077f5a 9
DanielC 0:7e65f5077f5a 10 /** Object representation of a sonar instance
DanielC 0:7e65f5077f5a 11 */
DanielC 0:7e65f5077f5a 12 class Sonar {
DanielC 0:7e65f5077f5a 13 public:
DanielC 0:7e65f5077f5a 14 /** Sets up the driver and starts taking measurements
DanielC 0:7e65f5077f5a 15 * @param input The pin to read pulses from
DanielC 0:7e65f5077f5a 16 * @param t A running timer instance used to measure pulse width.
DanielC 0:7e65f5077f5a 17 * Note that the timer must have been started or results will be
DanielC 0:7e65f5077f5a 18 * invalid.
DanielC 0:7e65f5077f5a 19 */
DanielC 0:7e65f5077f5a 20 Sonar(PinName input, Timer& t);
DanielC 0:7e65f5077f5a 21
DanielC 0:7e65f5077f5a 22 /// Returns range in cm as int
DanielC 0:7e65f5077f5a 23 int read();
DanielC 0:7e65f5077f5a 24
DanielC 0:7e65f5077f5a 25 /// Returns the range in CM as an int
DanielC 0:7e65f5077f5a 26 operator int();
DanielC 0:7e65f5077f5a 27
DanielC 0:7e65f5077f5a 28 private:
DanielC 0:7e65f5077f5a 29 /// Inturrupt at start of pulse
DanielC 0:7e65f5077f5a 30 void pulseStart();
DanielC 0:7e65f5077f5a 31 /// Interrupt at end of pulse
DanielC 0:7e65f5077f5a 32 void pulseStop();
DanielC 0:7e65f5077f5a 33
DanielC 0:7e65f5077f5a 34 /// Interrupt driver for the input pin
DanielC 0:7e65f5077f5a 35 InterruptIn interrupt;
DanielC 0:7e65f5077f5a 36 /// Reference to global timer instance
DanielC 0:7e65f5077f5a 37 Timer& time;
DanielC 0:7e65f5077f5a 38 /// Time of the start of the current pulse
DanielC 0:7e65f5077f5a 39 int pulseStartTime;
DanielC 0:7e65f5077f5a 40 /// The most recent sample
DanielC 0:7e65f5077f5a 41 int range;
DanielC 0:7e65f5077f5a 42 };