How does it work

Published March 24, 2020 © GPL3+

Ultrasonic distance sensor

In times of Corona, it is very important to keep distance

BeginnerWork in progress1 hour1,342

Things used in this project

Hardware components

Arduino UNO

Solderless Breadboard Full Size

SparkFun Solder-able Breadboard - Mini

LED (generic)

2x Red, 3xGreen

Resistor 220 ohm

Jumper wires (generic)

SparkFun Ultrasonic Sensor - HC-SR04

Story

As you all might know, the whole world suffers under this tiny little thing called Corona Virus. The Government of my home country decided to restrict public life. Because suddenly I had gotten a lot of free time, I decided to invest this time into Arduino. What you see here is the result of my first few days in quarantine.

The project itself (the code and structure) is very simple and I hope easy to understand and copy.

How does it work?

The ultrasonic sensor is able to send and receive ultrasonic waves. This gives us the opportunity to use it as a distance sensor. Objects in front of the sensor reflect those waves back to the sensor. Due to the time, the wave needs to return to the sensor and the knowledge of how fast a sonic wave moves, we are able to calculate the distance between the sensor and the objects which reflects the wave.

The formula

We need a formula which contains speed, time and distance calculate the distance.

Speed formula

v = speed in meters per second (m/s)

d= distance in meter (m)

t= time seconds (s)

Now we need to change the formula to be able to calculate the time. To do this, we multiply both sides by t:

Changed formular

Now we know to calculate the distance.

The data

It is important to adjust the data to the formula and the units which are used by our microcontroller.

Time (t): The sensor measures the time from the moment the wave being sent to moment the wave returns to the sensor. Since we are only interested in the distance between and the object we need to halve our time by divide by 2.

Speed (v): Sonic moves by 343, 2 meters per second (m/s). We have to adjust the unit of Speed. From meters per second to centimetre per microsecond, because the microcontroller measures time in microseconds.

343, 2 meter per second (m/s) = 0, 03432 centimeter per microsecond (cm/μs)

Time = pulseIn(echo, HIGH); // Reads a pulse on a pin in μs
distance = 0.03432 * (Time/2); // our formula to calculate the distance :) d=v*t

Code

int trigger = 7;
int echo = 6;
long Time = 0;
long  distance = 0;
int G1 = 12;
int G2 = 11; //
int G3 = 10; //
int R4 = 9; //
int R5 = 8; //
int Abstand = 90;
int Zeit = 50;

void setup ()
{
  Serial.begin(9600);
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(G1, OUTPUT);
  pinMode(G2, OUTPUT);
  pinMode(G3, OUTPUT);
  pinMode(R4, OUTPUT);
  pinMode(R5, OUTPUT);
  }

void loop()
{
  digitalWrite(trigger, LOW);
  delay(5);
  digitalWrite(trigger, HIGH);
  delay(10);
  digitalWrite(trigger, LOW);
  Time = pulseIn(echo, HIGH);
  distance = (Time/2) * 0.03432; //
 
if (distance >= 500 || distance <= 0)
    {Serial.println("Kein Messwert");}
else
 {Serial.print(distance);
  Serial.println("cm");}

 delay(50);

if (distance <= Abstand)
{digitalWrite(G1, HIGH);
}

else 
{
digitalWrite(G1, LOW);
}


if (distance <= Abstand - 50)
{ digitalWrite(G2, HIGH);}

else 
{digitalWrite(G2, LOW);}


if (distance <= Abstand - 60)
{digitalWrite(G3, HIGH);}

else 
{ digitalWrite(G3, LOW);}

if (distance <= Abstand - 70)
{digitalWrite(R4, HIGH);}

else 
{digitalWrite(R4, LOW);}

if (distance <= Abstand - 80)
{digitalWrite(R5, HIGH);}

else 
{digitalWrite(R5, LOW);




}

 delay(5);
 
}

Credits

Pericardium

1 project • 0 followers

Ultrasonic distance sensor

Things used in this project

Hardware components

Story

How does it work?

Schematics

Sketch

Code

Untitled file

Video

Credits

Pericardium

Comments

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Ultrasonic distance sensor

Ultrasonic distance sensor

Things used in this project

Hardware components

Story

How does it work?

Schematics

Sketch

Code

Untitled file

Video

Credits

Pericardium

Comments

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