This document describes a door alert system called DAD that detects when a visitor arrives and alerts deaf residents. It uses an Arduino Uno, infrared distance sensor, LED, and code to sense when a person is near the gate. When detected, the sensor sends a signal to the Arduino board which triggers the LED to light or sends a computer message to alert the deaf person inside of the visitor. The system works through an infrared sensor detecting objects and sending signals to an Arduino board that controls the LED based on the signal value.

1. In this fast moving world people come and go from one place to another, greeting all
who meet on the way and answering the strangers in the most polite manner possible.
But the same world proves very difficult for those in our society who cannot hear: the deaf. When a
person visits a place, we first ring the bell on the doorpost. This cannot be heard by an old man or a deaf
person who resides at his home.
Here comes the action of our application:
When a visitor comes, a sensor which is attached to the gate detects the presence of a person and alerts
the deaf man inside by either lighting a bulb or through a computer message, if the person is working on a
computer.
How does it work?
The technological aspect is as follows:
 Arduino Uno
 IR Distance Sensor
 Wires and Printed circuits boards
 Led Red
 Arduino Compiler
Working:
Arduino Uno takes the signal from IR Distance sensor , IR distance sensor sense the object . In Arduino
Uno Board there is input pin and and analog pin , IR distance sensor connect with analog pin to read the
signal from sensor and leds are coonected to input pin A9.When an object come near to the sensor the
sensor send the signal to the analog pin and it converted into digital signal,when the signal is 1 the led will
blink when the signal is 0 it will not blink.
DOOR ALERT SYSTEM FOR DEAF PEOPLE “DAD”

2. Source Code:
const int ledPin = 13; // led connected to digital pin 13
const int knockSensor = A0; // the piezo is connected to analog pin 0
const int threshold = 100; // threshold value to decide when the detected sound is a knock or not
// these variables will change:
int sensorReading = 0; // variable to store the value read from the sensor pin
int ledState = LOW; // variable used to store the last LED status, to toggle the light
void setup() {
pinMode(ledPin, OUTPUT); // declare the ledPin as as OUTPUT
Serial.begin(9600); // use the serial port
}
void loop() {
// read the sensor and store it in the variable sensorReading:
sensorReading = analogRead(knockSensor);
// if the sensor reading is greater than the threshold:
if (sensorReading >= threshold) {
// toggle the status of the ledPin:

3. ledState = !ledState;
// update the LED pin itself:
digitalWrite(ledPin, ledState);
// send the string "Knock!" back to the computer, followed by newline
Serial.println("Hey You Deaf Open the Door .");
}
delay(100); // delay to avoid overloading the serial port buffer
}