com.raspoid.additionalcomponents

Class UltrasonicHCSR04

java.lang.Object

com.raspoid.GPIOComponent

com.raspoid.additionalcomponents.UltrasonicHCSR04

All Implemented Interfaces:

Component

public class UltrasonicHCSR04
extends GPIOComponent

Ultrasonic ranging module HCSR04 provides 2cm - 400cm non-contact measurement function. The ranging accuracy can reach to 3mm. The modules includes ultrasonic transmitters, receiver and control circuit.

The basic principle of work:

• (1) Using IO trigger for at least 10us high level signal,
• (2) The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back.
• (3) If the signal back, through high level, time of high output IO duration is the time from sending ultrasonic to returning.

distance = (high level time X velocity of sound (340M/S) / 2

Datasheet: HCSR04

Note: for accuracy reasons, we need to directly use WiringPi functions instead of pi4j to control the pins, probably because pi4j is too slow to react (higher level).

Examples of use: UltrasonicHCSR04Example and UltrasonicSensorsComparison

Field Summary

Fields inherited from class com.raspoid.GPIOComponent

gpio

Constructor Summary

Constructors

Constructor and Description
UltrasonicHCSR04(GPIOPin trigPin) Constructor for a variant of ultrasonic sensor HCSR04 using a signle Gpio pin for trigger and echo signals.
UltrasonicHCSR04(GPIOPin trigPin, GPIOPin echoPin) Constructor for an ultrasonic sensor HCSR04 using a specific Gpio trigger pin and a specific Gpio echo pin.

Method Summary

Modifier and Type	Method and Description
double	getDistance() Get the calculated distance from the ultrasound sensor.

Methods inherited from class com.raspoid.GPIOComponent

getType

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UltrasonicHCSR04

public UltrasonicHCSR04(GPIOPin trigPin,
                        GPIOPin echoPin)

Constructor for an ultrasonic sensor HCSR04 using a specific Gpio trigger pin and a specific Gpio echo pin.

Parameters:

trigPin - the pin to use to trigger signals.

echoPin - the pin to use to detect echo signals.

UltrasonicHCSR04

public UltrasonicHCSR04(GPIOPin trigPin)

Constructor for a variant of ultrasonic sensor HCSR04 using a signle Gpio pin for trigger and echo signals.

Parameters:

trigPin - the Gpio pin used for trigger and echo signals.

Method Detail

getDistance

public double getDistance()

Get the calculated distance from the ultrasound sensor.

By measuring the width of the echo pulse and dividing by 58 to get distance in cm [cfr datasheet].

Returns:

the measured distance, in cm.