TVZ Mechatronics Team / HCSR04

A distance measurement class using ultrasonic sensor HC-SR04.

Dependents:   Esercitazione4_4 HC-SR04 Group10_slave Oled_Gus ... more

The purpose of this library is to encourage students to develope their own classes. Instructions how to follow the development of this library for ultrasonic distance measurement are given here.

HCSR04.h

Committer:
tbjazic
Date:
2015-12-06
Revision:
3:9a7899cf5e3a
Parent:
2:aa59a9c531be
Child:
4:aae70f15357f

File content as of revision 3:9a7899cf5e3a:

#ifndef HCSR04_H_TVZMT
#define HCSR04_H_TVZMT

/** A distance measurement class using ultrasonic sensor HC-SR04.
 *  
 * Example of use:
 * @code
 * #include "mbed.h"
 * #include "HCSR04.h"
 *
 * Serial pc(USBTX, USBRX);    // communication with terminal
 * 
 * int main() {
 *     HCSR04 sensor(p5, p7);     // instantiate the sensor object
 *     while(1) {
 *         pc.printf("Distance: %5.1f cm\r", sensor.getDistance_cm());
 *         wait_ms(975); // print the result every 1 second
 *     }
 * }
 * @endcode
 */
class HCSR04 {
    
    public:
    
    /** Receives two PinName variables.
     * @param echoPin mbed pin to which the echo signal is connected to
     * @param triggerPin mbed pin to which the trigger signal is connected to
     */
    HCSR04(PinName echoPin, PinName triggerPin);
    
    /** Calculates the distance in cm, with the calculation time of 25 ms.
     * @returns distance of the measuring object in cm.
     */
    float getDistance_cm();
    
    private:
    
    InterruptIn echo;       // echo pin
    DigitalOut trigger;     // trigger pin
    Timer timer;            // echo pulsewidth measurement
    float distance;         // store the distance in cm
    float minDistance;      // minimum measurable distance
    float maxDistance;      // maximum measurable distance
    
    /** Start the timer. */
    void startTimer();
    
    /** Stop the timer. */
    void stopTimer();
    
    /** Initialization. */
    void init();
    
    /** Start the measurement. */
    void startMeasurement();
};

#endif