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    (QUICK START GUIDE) Set Up An Ultrasonic Range Finder On An Arduino

    Uploaded by

    tharun sabinikari
    The document describes how to set up ultrasonic range finders on an Arduino to measure distance using sound pulses. It explains three circuits of increasing complexity: 1) a basic circuit that doesn't compensate for temperature, 2) one that uses a thermistor to factor temperature into distance calculations, and 3) one that uses a DHT11 humidity and temperature sensor to account for both temperature and humidity for more accurate measurements.

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    © All Rights Reserved
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    (QUICK START GUIDE) Set Up An Ultrasonic Range Finder On An Arduino

    Uploaded by

    tharun sabinikari
    120 views7 pages
    The document describes how to set up ultrasonic range finders on an Arduino to measure distance using sound pulses. It explains three circuits of increasing complexity: 1) a basic circuit that doesn't compensate for temperature, 2) one that uses a thermistor to factor temperature into distance calculations, and 3) one that uses a DHT11 humidity and temperature sensor to account for both temperature and humidity for more accurate measurements.

    Original Description:

    Tajsjejs

    Original Title

    [QUICK START GUIDE] Set Up an Ultrasonic Range Finder on an Arduino

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    The document describes how to set up ultrasonic range finders on an Arduino to measure distance using sound pulses. It explains three circuits of increasing complexity: 1) a basic circuit that doesn't compensate for temperature, 2) one that uses a thermistor to factor temperature into distance calculations, and 3) one that uses a DHT11 humidity and temperature sensor to account for both temperature and humidity for more accurate measurements.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    120 views7 pages

    (QUICK START GUIDE) Set Up An Ultrasonic Range Finder On An Arduino

    Uploaded by

    tharun sabinikari
    The document describes how to set up ultrasonic range finders on an Arduino to measure distance using sound pulses. It explains three circuits of increasing complexity: 1) a basic circuit that doesn't compensate for temperature, 2) one that uses a thermistor to factor temperature into distance calculations, and 3) one that uses a DHT11 humidity and temperature sensor to account for both temperature and humidity for more accurate measurements.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 7

    Circuit Basics

    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    QUICK START GUIDE


    How to Set Up an Ultrasonic Range Finder
    on an Arduino
    SUMMARY
    The HC-SR04 ultrasonic range finder uses sound to measure
    the distance to solid objects. This guide will show you how
    to build three different ultrasonic range finder circuits with MATERIALS
    an Arduino. The first circuit is simple and has good
    • Arduino Uno
    accuracy, but the second circuit factors in temperature for
    • Breadboard
    more accurate distance measurements. The third circuit
    • 16X2 LCD (Optional)
    factors in both temperature and humidity for the greatest
    • Jumper Wires
    accuracy.
    • Resistors
    • Thermistor
    How Ultrasonic Range Finders Work
    • DHT11 Humidity Sensor
    Ultrasonic range finders measure distance by emitting a • HC-SR04 Ultrasonic Range
    pulse of sound that travels through the air until it hits an Finder
    object. The pulse of sound is reflected off the object and is
    detected by the ultrasonic range finder. The time it takes the
    sound pulse to travel in its round trip journey back to the RESOURCES
    sensor is recorded and used to calculate the distance to the
    object with the formula: • Arduino Forums
    • Circuit Basics
    speed of sound = distance / time
    • DHTLib Library
    Rearranging this formula, we get:

    distance = speed of sound x time

    Temperature and Humidity Effects


    The speed of sound in air changes with temperature and
    humidity. Therefore, in order to accurately calculate distance
    we need to factor in temperature and humidity into our
    calculations.
    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    The formula for the speed of sound in air is:

    c = 331.4 + (0.606 x T) + (0.0124 x H)

    c = Speed of sound in meters per second (m/s)

    331.4 = Speed of sound (in m/s) at 0 °C and 0% humidity

    T = Temperature in °C

    H = % Humidity (relative humidity)

    The HC-SR04 ultrasonic range finder has four pins:

    Vcc = 5V power input used to generate the ultrasonic pulses.

    GND = Connected to ground.

    Trig = The Arduino sends a signal to this pin to start the distance measurement.

    Echo = The ultrasonic range finder returns the time data to the Arduino at this pin.
    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    A Basic Ultrasonic Range Finder Circuit


    This circuit doesn’t factor humidity or temperature into the speed of sound formula.

    Start by connecting the ultrasonic range finder to your Arduino:

    Now upload this code to the Arduino, then open the serial monitor to see the distance
    measurements:

    #define trigPin 10
    #define echoPin 13

    void setup() {
    Serial.begin (9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    }

    void loop() {
    float duration, distance;
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = (duration / 2) * 0.0344;

    if (distance >= 400 || distance <= 2){


    Serial.print("Distance = ");
    Serial.println("Out of range");
    }

    Program continued on next page…


    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    else {
    Serial.print("Distance = ");
    Serial.print(distance);
    Serial.println(" cm");
    delay(500);
    }
    delay(500);
    }

    Temperature Compensated Ultrasonic Range Finder Circuit


    The temperature data from a thermistor will allow us to get a more accurate calculation
    of the speed of sound.

    Connect the ultrasonic range finder and thermistor to your Arduino like this:

    R1 = 10K Ohm resistor

    Th = 10K Ohm thermistor

    If you want to use a 100K Ohm thermistor instead, change the resistor to 100K Ohms,
    and change line 7 in the code below to:
    Temp = log(100000.0*((1024.0/RawADC-1)));
    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    Now upload this program to the Arduino and open up the serial monitor:

    #include <math.h>
    #define trigPin 10
    #define echoPin 13

    double Thermistor(int RawADC) {


    double Temp;
    Temp = log(10000.0*((1024.0/RawADC-1)));
    Temp = 1/(0.001129148+(0.000234125+(0.0000000876741*Temp*Temp))*Temp);
    Temp = Temp - 273.15;
    return Temp;
    }

    void setup() {
    Serial.begin (9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    }

    void loop() {
    int val;
    double temp;
    val=analogRead(0);
    temp=Thermistor(val);

    float duration, distance;


    float spdSnd;
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);

    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH);


    spdSnd = 331.4 + (0.606 * temp) + 0.62;
    distance = (duration / 2) * (spdSnd / 10000);

    if (distance >= 400 || distance <= 2){


    Serial.print("Distance = ");
    Serial.println("Out of range");
    }
    else {
    Serial.print("Distance = ");
    Serial.print(distance);
    Serial.println(" cm");
    delay(500);
    }
    delay(500);
    }
    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    Temperature and Humidity Compensated Ultrasonic Range


    Finder Circuit
    You can get an even more accurate distance measurement by factoring humidity into
    the speed of sound equation.

    The DHT11 temperature and humidity sensor provides both temperature and
    humidity data. To use the DHT11 on the Arduino, you’ll need to install the DHTLib
    library on your computer. First, download the .zip file from here, then open your
    Arduino IDE and go to Sketch > Include Library > Add ZIP Library, then select the
    DHTLib.zip file.

    Now, connect the ultrasonic range finder and DHT11 to your Arduino:
    Circuit Basics
    Raspberry Pi, Arduino, and DIY Electronics Tutorials

    Next, upload this code to your Arduino and open the serial monitor:
    #include <dht.h>

    #define trigPin 10
    #define echoPin 13
    #define DHT11_PIN 7

    dht DHT;

    void setup() {
    Serial.begin (9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    }

    void loop() {

    float duration, distance;


    float speed;

    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH);


    speed = 331.4 + (0.606 * DHT.temperature) + (0.0124 * DHT.humidity);
    distance = (duration / 2) * (speed / 10000);

    if (distance >= 400 || distance <= 2){


    Serial.print("Distance = ");
    Serial.println("Out of range");
    }
    else {
    Serial.print("Distance = ");
    Serial.print(distance);
    Serial.println(" cm");
    delay(1000);
    }
    delay(1000);
    }

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