Automatic sanitizer dispenser using Arduino

Last Updated on December 30, 2020 by technoreview85

It is an automatic hand sanitizer dispenser circuit & Arduino code for making an automatic sanitizer dispenser machine.

How it works

For making this circuit I used Arduino Nano & HC SR 04 Ultrasonic sensor.

when any object detected by the ultrasonic sensor within 15cm then the Arduino Nano digital pin 8 became high. this D8 pin is connected to an NPN transistor’s base via a resistor so when an object is detected near sensor the transistor flow negative voltage to relay & the 5v relay turn on the 12v dc pump & the liquid sanitizer flows from the spray nozzle. please check the circuit diagram given below.

You need to make

Transistor 548b
5v relay
5 volt DC Regulator IC7805
Capacitor 470mf/25v
Resistor – 1 k, 220E
Led
Diode IN4007
5v mini buzzer ( Active buzzer)

Arduino nano
Hc sr 04 ultrasonic sensor
Female header
Terminal block 2 pin
Female to male jumper 4 wire
Vero board or Pref board

DC12V Self-Priming Diaphragm Pump
Low pressure spray nozzle (6mm)

Making circuit

Insert all components on pref board & connect asper circuit diagram

HC sr 04 trig pin connect to Arduino D2

HC sr 04 Echo pin connect to Arduino D3

connect buzzer + to Arduino D9 & D8 will be connected to the transistor base via 1K resistor.

Automatic sanitizer dispenser Arduino code

Now upload the code to Arduino Nano using Arduino IDE

//Ultasonic Sensor
// sanitizer dispenser arduino code by http://technoreview85.com/
//Pins connected to the ultrasonic sensor
#define trigPin  2
#define echoPin 3

#define pump 8
#define buzzer 9


int range = 7;//range in inches

void setup() {
  // initialize serial communication:
  Serial.begin(9600);
  //initialize the sensor pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);


  pinMode(pump, OUTPUT);
   pinMode(buzzer, OUTPUT);
 
  digitalWrite(pump, LOW);
  digitalWrite(buzzer, LOW);
  
}
void loop()
{
  // establish variables for duration of the ping, 
  // and the distance result in inches and centimeters:
  long duration, inches, cm;

  // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(trigPin, LOW);

  // Take reading on echo pin
  duration = pulseIn(echoPin, HIGH);

  // convert the time into a distance
  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);
  
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();
  
  if(inches < 7) {
    Serial.println("hand puted");
    
    digitalWrite(pump, HIGH);
    digitalWrite(buzzer, HIGH);
    delay(1200);
    digitalWrite(pump, LOW); 
    digitalWrite(buzzer,LOW);
    delay(3000);
  } else {
    Serial.println("no hand");
     
     digitalWrite(pump, LOW);
     digitalWrite(buzzer,LOW); 
     delay(50);
  }  
  
  delay(200);
}

long microsecondsToInches(long microseconds)
{

  return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{
  // The speed of sound is 340 m/s or 29 microseconds per centimeter.
  // The ping travels out and back, so to find the distance of the
  // object we take half of the distance travelled.
  return microseconds / 29 / 2;
}

You can copy the code form above or Download INO file from hear