Published November 10, 2025 © GPL3+

PCL-Home Automation-IndoorLightDetector

Uses a particle photon 2 device to send messages to my phone when the lights are on and there's nobody in a room.

IntermediateShowcase (no instructions)1.5 hours1

Things used in this project

Hardware components

Particle Photon 2

Photo resistor

5 mm

PIR Motion Sensor (generic)

HC-SR501 Pir Motion IR Sensor

Male/Female Jumper Wires

For the PIR sensor

Jumper wires (generic)

For the photoresistor/everything else* Number of wires may vary depending on how you wire it

Digilent USB A to Micro-B Cable

Any USB to Micro USB will work, needed to connect the computer/power supply to the photon.

Breadboard (generic)

Through Hole Resistor, 330 ohm

Software apps and online services

Particle Build Web IDE

Story

This project uses a PIR motion sensor in order to detect if there is a person in the room that it's in. If it doesn't detect movement for 15 minutes, it will trigger the photoresistor to check the light levels in that room. If the lights are on, it will send trigger a webhook to send a text message using pushover informing the owner that the lights are on.

Breadboard and PIR sensor

HowItWorks

when the device is on, the PIR motion sensor will be constantly scanning the room for motion using an infrared sensor. If it detects motion, it will reset the timer and display that there's motion and the light level in the room on a serial port, which you can check here if you want, (Spacehuhn Serial Terminal). If, in 15 minutes it doesn't detect motion, it will have the photoresistor check the amount of light in the room. If the lights are off, it will mention that in the serial port, then the PIR sensor will continue scanning. If the lights are on, then it will trigger a webhook in particle which will trigger an app called pushover to send you a notification that the lights are on.

Setup

CircuitDiagram

https://app.cirkitdesigner.com/project/dba2b47c-a2d9-4979-b482-e99df9e10aa6

PIRSensor

Use the male to female wires to connect the power prong to 3v3, output to D6, and the ground to GND, like in the diagram.

Turn both dials fully counterclockwise.

Coding

Go to the Particle Web IDE, and create an app called motionsensor.

Untitled file

// Include Particle Device OS APIs
#include "Particle.h"

// Let Device OS manage the connection to the Particle Cloud
SYSTEM_MODE(AUTOMATIC);


SerialLogHandler logHandler(LOG_LEVEL_INFO);

int photoresistorPin = A0;  
int lightValue = 0; 
int pirPin = D6;
int lastmove=0;
// A variable to hold the sensor's current state
int pirState = 0;
// This function runs once when the device is started
void setup() {
    Serial.begin(9600);
  // Set the PIR pin as an input
  pinMode(pirPin, INPUT);
  
}


void loop() {
  // Read the state of the PIR sensor
  pirState = digitalRead(pirPin);
int ti=millis();
if (pirState == HIGH) {
    lightValue = analogRead(photoresistorPin);
    Serial.println("Motion detected!");
    Serial.println("lightvalue= ");
    Serial.println(lightValue);
    lastmove=ti;
    delay(5000);
    // The PIR sensor also has a built-in delay based on your potentiometer setting
  }
else if(ti-900000==lastmove){
     lightValue = analogRead(photoresistorPin);
    if(lightValue>0){
    Serial.println("No motion, lights on");
    Serial.println("lightvalue= ");
    Serial.println(lightValue);
    Particle.publish("push-notification", "lights on");}
    else{
        Serial.println("No motion, lights off");
    }
    lastmove=ti;
    delay(1000);
  }
}

Credits

Nathan Charpentier

1 project • 0 followers

PCL-Home Automation-IndoorLightDetector

Things used in this project

Hardware components

Software apps and online services

Story

Setup

Coding

Code

Untitled file

Credits

Nathan Charpentier

Comments

Embed the widget on your own site

PCL-Home Automation-IndoorLightDetector

PCL-Home Automation-IndoorLightDetector

Things used in this project

Hardware components

Software apps and online services

Story

Setup

Coding

Code

Untitled file

Credits

Nathan Charpentier

Comments

Related channels and tags