To avoid contamination of COVID-19 we can use a touchless smart doorbell using cost-friendly sensors.

Smart Touch-less Doorbell :
The first COVID-19 case was first reported in January and after months it is in Lakhs all over the country. The outbreak has been declared an epidemic. According to the World Health Organization maintaining social distancing and keep yourself hygiene are the only ways to prevent contamination. But in this extreme situation, we can't avoid visiting anyone's place. In this scenario, we will use the doorbell but in this case, there is a high risk of contaminating the virus. This problem can be solved by making a touch-less doorbell where you can put your hand in front of the sensor and a buzzer sound will be generated from inside.

Step 1: Components Needed

The following components are needed to make the door-bell.

1. HC-SR04

2.Arduino UNO

3.Buzzer

4.Bread Board

5. Wires

Step 2: HC-SR04 Obstacle Avoidance Sensor

HC-SR04 is one of the popular ultrasonic sensors. It is commonly used to measure distance nearby ranges, but it was actually to detect the presence of nearby objects without any physical contact.

Check https://www.arduinoforbeginners.com/hc-sr04/

to know more about this sensor and how it works.