Make it Possible with Physics - Ultrasonic Thermometer!

In this tutorial, I will be giving the basics for an ultrasonic thermometer and the idea behind it.

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Make it Possible with Physics - Ultrasonic Thermometer!

Things used in this project

Hardware components

HC-SR04 Ultrasonic Sensor

Arduino UNO

Software apps and online services

Arduino IDE

Story

Introduction

This simple project is based on the idea that "speed of sound in air strictly depends on the ambient temperature" and this difference can be calculated by a short equation:

Speed of sound(meters/second)=331,4 + 0,6 x (ambient temperature in degrees celsius)

Things to keep in mind:

Speed of sound also depends on air flow (i.e. wind speed). If the environment you're planning to do this is windy, then do not expect accurate results.

The sensor module used in the project is quite cheap and low-end. So be aware that the readings are expected to be unstable.

Even so, it's possible to get acceptable readings +/- 2°C

Although the video is in Turkish language, it's useful to see the project working.

Code

Main Arduino Sketch

#define echo 7
#define trigger 8
double delaytime, temperature, speedofsound;

void setup(){
pinMode(trigger,OUTPUT);
pinMode(echo,INPUT);
Serial.begin(9600);
}

void loop(){
digitalWrite(trigger,LOW);
delayMicroseconds(2);         //Standard trigger-echo cycle provided by                              the manufacturer
digitalWrite(trigger,HIGH);
delayMicroseconds(10);
digitalWrite(trigger,LOW);

delaytime=pulseIn(echo,HIGH);
speedofsound=370000/delaytime;
temperature=(speedofsound-331.4)/0.6;
Serial.println(temperature);
delay(500);
}

Make it Possible with Physics - Ultrasonic Thermometer!