Development and testing of ultrasonic distance measurement library for device HC-SR04.

Dependencies:   TextLCD_improved mbed Distance_HC_SR04

Files at this revision

API Documentation at this revision

Comitter:
dzoni
Date:
Mon Dec 21 21:55:02 2015 +0000
Branch:
CLASS_IMPLEMENTATION
Parent:
6:1cec3aef9d86
Commit message:
Small touches...

Changed in this revision

Distance_HC_SR04.cpp Show diff for this revision Revisions of this file
Distance_HC_SR04.h Show diff for this revision Revisions of this file
Distance_HC_SR04.lib Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
--- 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;
-            }
-        }
-    }
--- a/Distance_HC_SR04.h	Mon Dec 21 20:56:52 2015 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,54 +0,0 @@
-#ifndef MBED_DISTANCE_HC_SR04_H
-#define MBED_DISTANCE_HC_SR04_H
- 
-#include "mbed.h"
- 
-#define TIMEOUT_DELAY_US    (25000)
-#define CALC_COEFF          (340.0f/(2.0f*1000.0f))
-#define TICKS_RANGE_MAX     (15000)
-#define TICKS_RANGE_MIN     (150)
-#define TRIG_PULSE_US       (50)
-
-typedef enum { IDLE, STARTED, COMPLETED, TIMEOUT, OUT_OF_RANGE_MIN, OUT_OF_RANGE_MAX, ERROR_SIG } Distance_HC_SR04_state;
-
-/** Distance_HC_SR04 class.
- *
- *  Library for interfacing ultrasonic distance measurement device HC-SR04.
- *  Functionality includes detection of error in echo signal, detection of timeout and limits of reliable measurement.
- *
- */
-class Distance_HC_SR04 {
-
-public:
-    Distance_HC_SR04(PinName trig, PinName echo, uint32_t tout_us = TIMEOUT_DELAY_US, float coeff = CALC_COEFF,
-            uint32_t tmin_us = TICKS_RANGE_MIN, uint32_t tmax_us = TICKS_RANGE_MAX);
-    void trigger(void);
-    Distance_HC_SR04_state getState(void);
-    void reset(void);
-    uint32_t getTicks(void);
-    float getDistance(void);
-    float getCoeff(void);
-    void setCoeff(float coeff);
-    float measureDistance(void);
-    uint32_t measureTicks(void);
-
-    void _tout(void);
-    void _rising(void);
-    void _falling(void);
-
-private:
-    DigitalOut  _trig;
-    InterruptIn _echo;
-    uint32_t    _tout_us;
-    float       _coeff;
-    uint32_t    _tmin_us;
-    uint32_t    _tmax_us;
-
-    Timer       _timer;
-    Timeout     _timeout;
-
-    volatile Distance_HC_SR04_state _state;
-    uint32_t                        _ticks_us;
-};
- 
-#endif
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Distance_HC_SR04.lib	Mon Dec 21 21:55:02 2015 +0000
@@ -0,0 +1,1 @@
+https://developer.mbed.org/users/dzoni/code/Distance_HC_SR04/#c516e180843e
--- a/main.cpp	Mon Dec 21 20:56:52 2015 +0000
+++ b/main.cpp	Mon Dec 21 21:55:02 2015 +0000
@@ -14,11 +14,6 @@
     wait_ms(250);
     lcd.cls();
 
-    lcd.cls();
-    lcd.printf("Row 1");
-    lcd.locate(0, 1);
-    lcd.printf("Row 2");
-
     Distance_HC_SR04 distFront(PB_9, PA_6);
     uint32_t ticks_us;
     float distance;