changed range conditions
Fork of HCSR04 by
HCSR04.h
- Committer:
- srsmitherman
- Date:
- 2013-12-12
- Revision:
- 2:3ebde19131af
- Parent:
- 0:5461d44a187c
File content as of revision 2:3ebde19131af:
/* File: HCSR04.h * Author: Robert Abad Copyright (c) 2013 * * Desc: driver for HCSR04 Ultrasonic Range Finder. The returned range * is in units of meters. * * To use this driver you must call the methods ::startMeas() * and ::getMeas(). The HCSR04 requires a trigger time of * 10 usec (microseconds) which is initiated by ::startMeas(). * If a successful measurement is made, getMeas() will return * RANGE_MEAS_VALID. If unsuccessful, initiate a new measurement. * * The datasheet for this device can be found here: * http://www.elecfreaks.com/store/download/product/Sensor/HC-SR04/HC-SR04_Ultrasonic_Module_User_Guide.pdf * * Below is some sample code: * * #include "mbed.h" * #include "HCSR04.h" * * #define PIN_TRIGGER (p14) * #define PIN_ECHO (p15) * * int main(void) * { * HCSR04 rangeFinder( PIN_TRIGGER, PIN_ECHO ); * float range; * * while (1) * { * rangeFinder.startMeas(); * wait(0.1); * if ( rangeFinder.getMeas(range) == RANGE_MEAS_VALID ) * { * printf("range = %f\n\r", range); * } * } * } */ #ifndef __HCSR04_H__ #define __HCSR04_H__ #include "mbed.h" #define MTRS_TO_INCH (39.3701) typedef enum { RANGE_MEAS_INVALID, RANGE_MEAS_VALID } etHCSR04_RANGE_STATUS; class HCSR04 { public: HCSR04( PinName pinTrigger, PinName pinEcho ); void startMeas(void); etHCSR04_RANGE_STATUS getMeas(float &rRangeMeters); private: DigitalOut trigger; Ticker triggerTicker; InterruptIn echo; Timer echoTimer; unsigned long measTimeStart_us; unsigned long measTimeStop_us; unsigned long dTime_us; etHCSR04_RANGE_STATUS status; void triggerTicker_cb(void); // trigger ticker callback function void ISR_echoRising(void); // ISR for rising edge void ISR_echoFalling(void); // ISR for falling edge }; #endif /* __HCSR04_H__ */