Published June 10, 2021 © GPL3+

Contactless Doorbell

Transform your doorbell, in these covid times!!!!

IntermediateShowcase (no instructions)5,423

Things used in this project

Hardware components

Arduino UNO

Ultrasonic Sensor - HC-SR04 (Generic)

SG90 Micro-servo motor

LED (generic)

Jumper wires (generic)

9V battery (generic)

Switch Actuator, Head for spring return push-button

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)

Digilent Mastech MS8217 Autorange Digital Multimeter

Story

Motivation:

During this covid situation, we are taking a lot of precautions to save ourselves from coronavirus, but there are high chances of carelessness which might lead to consequences.The idea behind this project was basically to reduce the spread of the virus, when someone enters our home the first thing that comes in contact with that person is our doorbell, and it's not always possible to sanitize everything around us. So why not transform our traditional bell into a contactless bell, which eliminates the contact and hence reduces the chances of spread.

Working:

Whenever a person arrives at our home, so instead of pressing the bell, the person can raise hand at a distance of around 10cm so that the ultrasonic sensor can sense the presence a person and bell will ring automatically using servo motor without any touch to the bell.The plus point of the solution is that the solution can be applied to our existing doorbells.

Code

Contactless Doorbell

#include <Servo.h>  
#define trigPin 3  
#define echoPin 2  
Servo servo;  
// int sound = 250; 
int pos = 0;  
int led = 5;
void setup() {  
Serial.begin (9600);  
pinMode(led, OUTPUT);
pinMode(trigPin, OUTPUT);  
pinMode(echoPin, INPUT);  
servo.attach(4);  
}  
void loop() {  
long duration, distance; 
 
digitalWrite(trigPin, LOW);  
delayMicroseconds(2);  
digitalWrite(trigPin, HIGH);  
delayMicroseconds(10);  
digitalWrite(trigPin, LOW);  
duration = pulseIn(echoPin, HIGH);  
distance = (duration/2) / 29.1;  
if (distance < 10) {  
Serial.println("the distance is less than 10");  
for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
    // in steps of 1 degree
    servo.write(pos);  
    digitalWrite(led, HIGH);// tell servo to go to position in variable 'pos'
    delay(5
    );                       // waits 15ms for the servo to reach the position
  }
  for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
    servo.write(pos); 
    digitalWrite(led, LOW);// tell servo to go to position in variable 'pos'
    delay(5);                       // waits 15ms for the servo to reach the position
  } 
}  
else {  
servo.write(0);  
}  
if (distance > 60 || distance <= 0){  
Serial.println("The distance is more than 60");  
}  
else {  
Serial.print(distance);  
Serial.println(" cm");  
}  
delay(500);  
}