Suraksha Card

3 min readJan 11, 2021

What is this?

The most effective approach to slowing down the spread of the coronavirus is to keep away from others; prevention is better than cure. It would be helpful if there were a device that could warn others to keep away from you.

That is the purpose behind the project: to alert others to maintain a 1-meter distance from you.

Things we need.

Here I use an ultrasonic sensor to measure the distance and Arduino will continuously analyse that distance. When the distance is measured less than 1 meter then the Arduino will turn on the buzzer.

Before starting we need to understand some components used in this circuit.

1. Arduino UNO

The Arduino Uno is a microcontroller board based on the ATmega328. It has 20 digital input/output pins (of which 6 can be used as PWM outputs and 6 can be used as analog inputs), a 16 MHz resonator, a USB connection, a power jack, an in-circuit system programming (ICSP) header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

2. HC-SR 04 Ultrasonic Sensor

The HC-SR04 Ultrasonic distance sensor consists of two ultrasonic transducers. The one acts as a transmitter which converts an electrical signal into 40 KHz ultrasonic sound pulses. The receiver listens for the transmitted pulses. If it receives them it produces an output pulse whose width can be used to determine the distance the pulse travelled.

3. Piezo Buzzer

Piezo buzzers are simple devices that can generate basic beeps and tones. They work by using a piezo crystal, a special material that changes shape when a voltage is applied to it. If the crystal pushes against a diaphragm, like a tiny speaker cone, it can generate a pressure wave which the human ear picks up as sound. Simple change the frequency of the voltage sent to the piezo and it will start generating sounds by changing shape very quickly.

4. 9V Rechargeable Battery

Here we design this “Social distancing reminder” as a portable device. So the battery backup is an essential thing. We can use a 9V rechargeable battery. This is a USB rechargeable battery. Alternatively, you can use a generic 9v battery.

How does it work?

I have designed this special wearable device to save yourself from COVID-19 virus. We can wear it like an ID card. Whenever someone will come within 1 meter from you, BUZZER will buzz and give you a reminder to keep a safe distance.

Schematics

Arduino Coding

int const trigPin = 6;
	int const echoPin = 5;
	int const buzzPin = 13;
	void setup()
	{
	pinMode(trigPin, OUTPUT);
	pinMode(echoPin, INPUT);
	pinMode(buzzPin, OUTPUT);
	}
	void loop()
	{
	int duration, distance;
	digitalWrite(trigPin, HIGH);
	delay(1);
	digitalWrite(trigPin, LOW);
	duration = pulseIn(echoPin, HIGH);
	distance = (duration/2) / 29.1;
	if (distance <= 100 && distance >= 0) {
	digitalWrite(buzzPin, HIGH);
	} else {
	digitalWrite(buzzPin, LOW);
	}
	delay(60);}