Automatic Touchless Doorbell to Protect From Corona

I build this Arduino-based touchless doorbell using an MQ3 sensor that rings whenever a person waves his hand in front of the bell w.r.t. a distance. The best part is, the bell works only if the person has sanitized hands.

A doorbell is an indicator/informative device typically placed near a door to a house/building entrance. When a guest/sightseer presses a button at the entrance gate, the doorbell rings inside the house/building, which alerts the owner/householder to the presence of the guest/sightseer. Continue touching the bell switch by different people is harmful as sars-cov-2 coronavirus communicates via touching anything that already comes in touch with the infected person. So protection from coronavirus at the entrance (doorbell switch) is necessary.

Hand sanitization is one among all good precautions to prevent transmission of the novel coronavirus (sars-cov-2) in addition to social distancing.CDC (centers for disease control and prevention) recommends using hand sanitizer which at least contains 60 to 80% alcohol. The hand sanitizer available in markets contains ethanol with some other ingredients.

Here in our proposed project we designed and implemented a Corona Protected Automatic Touchless Doorbell with the help of interfacing of Arduino which rings automatically only when user/ guest/sightseer hands are sanitized by hand sanitizer. When someone wants to ring the bell he/she should show his/her hands just 3 to 5 cm. apart in front of the mq3 sensor (this sensor is the heart of our proposed project).

When someone wants to ring the bell, he/she should put his/her hands in front of the MQ3 sensor after sanitizing hands (2 to 5 cm. distance).

At this moment mq3 generates an analog output which will drive the interfaced Arduino-Uno to generate a signal at pin-8 and pin- 9. 

Here the LED is connected to pin-8 which will glow when mq3 senses the odor of sanitizer.

Pin 9 is connected to ULN2003IC which actually drives the relay at the same time and the relay is connected to the doorbell so it will ring.

#define MQ3 A0

#define Threshold 420

int value;

void setup() {

pinMode(MQ3, INPUT);

pinMode(8, OUTPUT);

pinMode(9, OUTPUT);

Serial.begin(9600);

}

void loop () {

value = analogRead(MQ3);

Serial.println(value);

if ( value > Thresold )

{

digitalWrite ( 8, HIGH );

digitalWrite ( 9 , HIGH );

}

else {

digitalWrite(8, LOW);

digitalWrite(9, LOW);

}

delay (500);

}