LED Night Light With PIR and LDR Sensors

This LED night light has many implications in everyday life such as a night light for the elderly who may have trouble seeing in the dark, During my research I found similar projects with an LDR but not containing a PIR sensor, so I decided to give it a go.

This LED night light project including a PIR and LDR sensor can detect the difference between day and night, It also utilizes a motion sensor to detect movement which then turns on the LED.

• Arduino uno 3
• PIR sensor
• LDR sensor
• LED x2
• wires
• 330 ohm resistor x3
• female to male or female to female jumper wires 3x

The most essential part of the project is wiring the components necessary for the project to even work

1, PIR: connect the VCC pin to power on the breadboard and the GND pin to ground, then connect the output pin to Arduino pin 10

2, LDR: connect one pin of the LDR to a 330 ohm resistor which then goes to power, the other pin should go directly to ground, Connect a wire where the LDR meets the resistor to Arduino analog pin 0

3, LED: Provide ground to both LED cathode pins which are shorter (negative), and connect a resistor to both anode (positive) pins which are connected to a wire which meets a wire providing power connected to Arduino Uno pin 9 ( to control LEDs at the same time using the same code)

4, Connect GND to ground on the Arduino as 5v to power

The code is equally as important for the successful operation of the project:

Void setup is the initial code run when the Arduino is turned off and on which initializes necessary settings to run your code such as declaring inputs and outputs. serial begin declares the speed at which data travels (bits)a

// Code for LED Night Light

This is where you established the pins for the components used in the project

v const int ldrPin = A0; // LDR pin

const int pirPin = 10;  // PIR sensor pin

const int ledPin = 9; // LED pin

Now we create a variable called night threshold and define the amount

// Define a threshold for night 

const int nightThreshold = 900;

Now we define the rate at which data is transmitted to the serial monitor

void setup() {

 // Initialize data travel speed at 9600 bits per second standard

 Serial.begin(9600);

Defining our components as inputs our outputs

 // Set pin modes

 pinMode(ldrPin, INPUT);

 pinMode(pirPin, INPUT);

 pinMode(ledPin, OUTPUT);

}

Our main code that makes the project work and loops on repeat :

void loop() {

 // Read the LDR value

 int ldrValue = analogRead(ldrPin); Telling the Arduino to read the LDR value

 // Print LDR value for debugging

 Serial.print("Ldr Value: "); telling the Arduino to display data from LDR to Monitor

 Serial.println(ldrValue);

 // Check if it's night (LDR value below the night threshold)

 if (ldrValue > nightThreshold) { Telling the Arduino to check if the number the LDR is detecting

  // Read PIR sensor is above the threshold variable we made earlier and if so to read

   int pirValue = digitalRead(pirPin); the PIR sensor for motion

 // Print PIR value for debugging

   Serial.print("Pir Value: "); Telling the Arduino to display the PIR value to the serial monitor

   Serial.println(pirValue);

 // If PIR sensor is HIGH, turn on the LEDs Telling the the Arduino if the PIR detects motion turn on the LEDS

 if (pirValue == HIGH) { and display it onto the monitor, and if not the LEDs should stay

   digitalWrite(ledPin, HIGH); // Turn on LEDs OFF and display No motion detected LEDS OFF to monitor

   Serial.println("Motion Detected Leds ON");

  } else {

   digitalWrite(ledPin, LOW); // Turn off LEDs

   Serial.println("No motion detected Leds OFF");

  }

 }  else {

 digitalWrite(ledPin, LOW);   // Turn off LEDs This code correlates with the first part of the code if the LDR

   Serial.println("Daytime LEDs OFF"); detects day instead of light the LEDS stay off and display onto the

  } Monitor

 }

Upload your code from the Arduino application to the Arduino via a wire and you're good to go!

Above is a video on the working night light