Automatic Hand Sanitizer Dispenser using Arduino | DIY Contactless Hand Sanitizer

Automatic Hand Sanitizer Dispenser using Arduino

Today, we are going to make an automatic hand sanitizer dispenser using an Arduino board. As you all know, COVID-19 is spreading like wildfire and all you hear is, wear a mask, clean your hands, use contactless alternatives, and practice social distancing.

Why Contactless Hand Sanitizer Dispenser using Arduino?

Hand sanitizer is one of the best ways to get rid of all the harmful germs and viruses in our hands. But what if a healthy person uses a hand sanitizer, which was previously used by a person who was infected by COVID19? In this case, there is a chance of spreading the virus.

In this post, we will build an automatic hand sanitizer dispenser which will help you to dispose of hand sanitizer without contact. You will find complete details and the code in the link below. This is an easy project that can be set up in a few minutes.

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Things Needed to make Contactless Hand Sanitizer Dispenser

All you need is a Breadboard, Arduino, Transistor, Ultrasonic sensor and a 12 V pump.

How Automatic Hand Sanitizer Dispenser using Arduino works?

So let’s get started. Here, we use an ultrasonic sensor to calculate the distance of our hand from the sensor. If the hand is close to the dispenser, Arduino will activate the pump and the sanitizer will be expelled out of the bottle through the tube.

Ultrasonic Sensor

An ultrasonic sensor is a device that is capable of transmitting and receiving ultrasonic sound waves out into the air and calculates the distance from the sensor to the obstacle by making use of the time required for the sound wave to reach back the sensor. If you are not sure about the Ultrasonic sensor and distance calculation, we have an entire article just for that. I will leave the link here. 

Using this, we can calculate the distance of our hands from the dispenser bottle. If the hand is right below the valve, that is 5 cm from the sensor, we turn on the pump using a transistor which is connected to pin 5 of the Arduino. 

How to make Automatic Hand Sanitizer Dispenser using Arduino?

Contactless Hand Sanitizer Dispenser Circuit

So here is the circuit. Here we have a 12V DC adapter that is connected to the Vin of Arduino and to the Positive terminal of the pump. D2 and D3 are connected to Echo and Trigger pin respectively. And D5 is connected to the Transistor. When the transistor switches On, the pump will get turned on. Here, one end of the pump is connected to the tube that goes inside the sanitizer bottle and the other end is held free.

Arduino Code

Let’s take a look at the code.

#define echoPin 2
#define trigPin 3

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(5, OUTPUT);
  Serial.begin(9600);
}
void loop() {
 
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);

  distance = duration * 0.034 / 2;
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  if (distance<=3)
  {
    digitalWrite(5, HIGH);
    Serial.print("Pump On");
    delay(150);
    digitalWrite(5, LOW);
    Serial.print("Pump OFF");
    delay(2000);
  }
  else
  {
    digitalWrite(5, LOW);
    Serial.print("Pump OFF");
  
  }
  delay(50);
}

The code is pretty simple. Here we initialize the pins, the echo pin, the trigger pin and the pump, set the pinmode and initialize the serial interface. Then, we make use of the Ultrasonic sensor to measure the distance from the hand, convert it to centimeters and store the value in the variable distance. In the final step, we write a condition to turn on Pin 5 for a particular duration when the hand is close to the sanitizer bottle.

Testing

Connect the board. Select the right port and board and hit upload.

That’s it, guys. The automatic sanitizer dispenser is now ready. Now put everything together and try bringing your hands close to the bottle.