TVZ Mechatronics Team / HCSR04

A distance measurement class using ultrasonic sensor HC-SR04.

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

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HCSR04 Class Reference
Public Member Functions

HCSR04 Class Reference

A distance measurement class using ultrasonic sensor HC-SR04. More...

#include <HCSR04.h>

Public Member Functions

 HCSR04 (PinName echoPin, PinName triggerPin)
 Receives two PinName variables.
void startMeasurement ()
 Start the measurement.
float getDistance_cm ()
 Returns the distance in cm.
float getDistance_mm ()
 Returns the distance in mm.
void setRanges (float minRange, float maxRange)
 Sets the minimum and maximum ranges between the factory values of 2 cm and 400 cm.
float getMinRange ()
 Retreives the minimum sensor range set by the user.
float getMaxRange ()
 Retreives the maximum sensor range set by the user.
bool isNewDataReady ()
 Checks if the new data is ready.

Detailed Description

A distance measurement class using ultrasonic sensor HC-SR04.

Example of use: 

 #include "mbed.h"
 #include "HCSR04.h"

 Serial pc(USBTX, USBRX);
 Timer timer;

 int main() {
     HCSR04 sensor(p5, p7);
     sensor.setRanges(10, 110);
     pc.printf("Min. range = %g cm\n\rMax. range = %g cm\n\r",
       sensor.getMinRange(), sensor.getMaxRange());
     while(true) {
         timer.reset();
         timer.start();
         sensor.startMeasurement();
         while(!sensor.isNewDataReady()) {
             // wait for new data
             // waiting time depends on the distance
         }
         pc.printf("Distance: %5.1f mm\r", sensor.getDistance_mm());
         timer.stop();
         wait_ms(500 - timer.read_ms()); // time the loop
     }
 }

Definition at line 34 of file HCSR04.h.

Constructor & Destructor Documentation

HCSR04 ( PinName  echoPin,
PinName  triggerPin 
)

Receives two PinName variables.

Parameters:
echoPinmbed pin to which the echo signal is connected to
triggerPinmbed pin to which the trigger signal is connected to

Definition at line 4 of file HCSR04.cpp.

Member Function Documentation

float getDistance_cm (  )

Returns the distance in cm.

Requires previous call of startMeasurement().

Returns:
distance of the measuring object in cm.

Definition at line 52 of file HCSR04.cpp.

float getDistance_mm (  )

Returns the distance in mm.

Requires previous call of startMeasurement().

Returns:
distance of the measuring object in mm.

Definition at line 57 of file HCSR04.cpp.

float getMaxRange (  )

Retreives the maximum sensor range set by the user.

Returns:
the maximum sensor range set by the user in cm.

Definition at line 79 of file HCSR04.cpp.

float getMinRange (  )

Retreives the minimum sensor range set by the user.

Returns:
the minimum sensor range set by the user in cm.

Definition at line 75 of file HCSR04.cpp.

bool isNewDataReady (  )

Checks if the new data is ready.

Returns:
true if new data is ready, false otherwise.

Definition at line 62 of file HCSR04.cpp.

void setRanges ( float  minRange,
float  maxRange 
)

Sets the minimum and maximum ranges between the factory values of 2 cm and 400 cm.

Parameters:
minRangeMinimum range in cm. Must be between 2 cm and maxRange.
maxRangeMaximum range in cm. Must be between minRange and 400 cm.

Definition at line 66 of file HCSR04.cpp.

void startMeasurement (  )

Start the measurement.

Measurement time depends on the distance. Maximum measurement time is limited to 25 ms (400 cm).

Definition at line 45 of file HCSR04.cpp.

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