Introduction:

This project aims for an advanced protection system of our food. By taking the help of modern engineering and technology we are trying to build an ultrasonic wave based protection system which is going to detect the falling of insects, lizards on food container. It detects the lizards and activates a danger alarm automatically. In a mid day meal program, it prevents the distribution of poisonous and contaminated food to school students. In this way it saves the lives of school children from food poisoning.

Materials required:

1. Battery
2. Buck converter
3. Ultrasonic sensor
4. Capacitor
5. Resistor
6. Transistor
7. LED
8. buzzer
9. Switch
10. Nodemcu  

Block diagram:

Working:

The ultrasonic wave guards the surface area of the food container. When a lizard falls vertically downward, the ultrasonic sensor detects the object and sends a signal to microcontroller. Then both buzzer and red LED are activated to provide a danger signal.

Advantage:

1. This alerts about the contamination of mid day meal.
2. This prevents food poisoning of students and saves their lives.

Code for microcontroller:

//Su-Din Technology
/*Ultrasonic sensor 
 obstacle detector.*/
int const trigPin=16; //D0
int const echoPin=05; //D1
int const buzzPin=04; //D2
int const relayPin=02; //D4

void setup() {
pinMode(trigPin,OUTPUT);
pinMode(echoPin,INPUT);
pinMode(buzzPin,OUTPUT);
pinMode(relayPin,OUTPUT);
             }

void loop() {
  // put your main code here, to run repeatedly:
int duration,distance;
digitalWrite(trigPin,HIGH);
delay(1);
digitalWrite(trigPin,LOW);
duration=pulseIn(echoPin,HIGH);
distance=(duration/2)/29.1;
if(distance<=25 && distance>=0)
  {
    digitalWrite(buzzPin,HIGH);
    delay(2000);
    digitalWrite(buzzPin,LOW);
    delay(1000);
    digitalWrite(buzzPin,HIGH);
    delay(2000);
    digitalWrite(buzzPin,LOW);
    delay(1000);
    digitalWrite(buzzPin,HIGH);
    delay(2000);
    digitalWrite(buzzPin,LOW);
    delay(1000);
    digitalWrite(buzzPin,HIGH);
    delay(2000);
    digitalWrite(buzzPin,LOW);
    delay(1000);
    digitalWrite(buzzPin,HIGH);
    delay(2000);
    digitalWrite(buzzPin,LOW);
    delay(1000);
  }
else
  {
    digitalWrite(buzzPin,LOW);
  }
delay(50);  
}

Designer:
Er. Anil Kumar Prusty
Phone No. :- +91 9861004895