Development and testing of ultrasonic distance measurement library for device HC-SR04.
Dependencies: TextLCD_improved mbed Distance_HC_SR04
Diff: Distance_HC_SR04.cpp
- Branch:
- CLASS_IMPLEMENTATION
- Revision:
- 7:cdde5cc8b2b3
- Parent:
- 6:1cec3aef9d86
--- a/Distance_HC_SR04.cpp Mon Dec 21 20:56:52 2015 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,181 +0,0 @@ -#include "Distance_HC_SR04.h" - - - /** Create Distance_HC_SR04 instance - */ - Distance_HC_SR04::Distance_HC_SR04(PinName trig, PinName echo, uint32_t tout_us, float coeff, - uint32_t tmin_us, uint32_t tmax_us) : - _trig(trig), _echo(echo), _tout_us(tout_us), _coeff(coeff), _tmin_us(tmin_us), _tmax_us(tmax_us) { - _trig = 0; - _state = IDLE; - } - - /** Start the measurement. - * - */ - void Distance_HC_SR04::trigger(void) { - if (_state == IDLE && _echo == 0) { - _timeout.detach(); - _echo.rise(NULL); - _echo.fall(NULL); - _timer.stop(); - _timer.reset(); - - _trig = 1; - wait_us(TRIG_PULSE_US); - _trig = 0; - - if (_echo == 0) { - _state = STARTED; - _timeout.attach_us(this, &Distance_HC_SR04::_tout, TIMEOUT_DELAY_US); - - _echo.rise(this, &Distance_HC_SR04::_rising); - _echo.fall(this, &Distance_HC_SR04::_falling); - - return; - } - } - - if (_state == IDLE) { - _state = ERROR_SIG; - _ticks_us = 0; - } - - return; - } - - /** Returns a state measurement FSM is currently in. - * - */ - Distance_HC_SR04_state Distance_HC_SR04::getState(void) { - return _state; - } - - /** Resets whole device and prepares for triggering next measurement. FSM set to IDLE state. - * - */ - void Distance_HC_SR04::reset(void) { - _state = IDLE; - _echo.rise(NULL); - _echo.fall(NULL); - _timeout.detach(); - _timer.stop(); - _timer.reset(); - } - - /** Returnes duration of "echo" pulse (microseconds) in case thate state is "COMPLETED". - * - */ - uint32_t Distance_HC_SR04::getTicks(void) { - return _ticks_us; - } - - /** Returns a distance of the obstacle in milimeters calculated from duration of "echo" pulse. - * - */ - float Distance_HC_SR04::getDistance(void) { - return _ticks_us*_coeff; - } - - /** Return actual value of coefficient used to calculate distance from "echo" pulse duration. - * - */ - float Distance_HC_SR04::getCoeff(void) { - return _coeff; - } - - /** Set the actual value of coefficient used to calculate distance from "echo" pulse duration. - * - * @param coeff Coeficient for multiplication with pulse duration in microseconds - * @returns - * void - */ - void Distance_HC_SR04::setCoeff(float coeff) { - _coeff = coeff; - } - - /** Measure and return the distance. - * - * @param void - - * @returns - * float value of distance > 0.0f in case of a success, - * 0.0f in case of an error - */ - float Distance_HC_SR04::measureDistance(void) { - return measureTicks()*_coeff; - } - - /** Measure and return "echo" pulse duration. - * - * @param void - - * @returns - * uint32_t value of distance > 0 in case of a success, - * 0 in case of an error - */ - uint32_t Distance_HC_SR04::measureTicks(void) { - reset(); - trigger(); - - while (_state == STARTED) - ; - - _echo.rise(NULL); - _echo.fall(NULL); - _timeout.detach(); - - switch (_state) { - case COMPLETED: - break; - default: - _ticks_us = 0; - break; - } - - return _ticks_us; - } - - /** Timeout callback function. - * - * @param void - - * @returns - * void - - */ - void Distance_HC_SR04::_tout(void) { - if (_state == STARTED) - _state = TIMEOUT; - } - - /** Rising edge callback function. - * - * @param void - - * @returns - * void - - */ - void Distance_HC_SR04::_rising(void) { - if (_state == STARTED) { - _timer.start(); - } - } - - /** Falling edge callback function. - * - * @param void - - * @returns - * void - - */ - void Distance_HC_SR04::_falling(void) { - if (_state == STARTED) { - _timer.stop(); - _ticks_us = _timer.read_us(); - - if (_ticks_us < _tmin_us) { - _ticks_us = 0; - _state = OUT_OF_RANGE_MIN; - } else if (_ticks_us > _tmax_us) { - _ticks_us = 0; - _state = OUT_OF_RANGE_MAX; - } else { - _state = COMPLETED; - } - } - }