Published December 13, 2024

Automatic Dog Lightswitch

Create an automatic light switch when your dog enters the room at night and no other light is present.

IntermediateFull instructions provided38

Things used in this project

Hardware components

Breadboard (generic)

Particle Photon 2

PIR Motion Sensor (generic)

SG90 Micro-servo motor

LDR, 5 Mohm

Resistor 1k ohm

Story

This project was part of the Lane Tech HS Physical Computing Lab course. I created this project as part of the Home Automation / IoT project.

I decided to create a system that will automatically turn on the room light when my dog enters the room at night and there is no other light present in the room. It's purpose is to ensure my dog has enough light to move around the room safely, especially when no one else is home and it’s dark outside or in the house.

Setup

I began by testing each of my components to ensure they functioned properly. I tested each individual component by spinning the servo to check if they were working correctly. First, I tested the motion sensor. If it returned a HIGH signal, I would spin the servo. Next, I tested the LDR sensor. After researching and testing the range of values it returns, I determined that, for the conditions of my project, a value less than 450 would signify no light present in the room. Finally, I used the Particle Time class, which requires you to set your time zone (Time Zone Documentation), to ensure the system would only operate after 4 PM (when Time.hour() returns 16). Once I confirmed that each of my components worked as intended, I moved on to the next step.

Completion

I combined all the components into one circuit and then determined that it would be best to use external power. As for the code, I created a single if statement that checked three conditions: if there was no light in the room, if the time was between 4 PM and midnight, and if motion was detected. If all three conditions were true, the servo would spin to flick the light switch.

External Power Split

Installation

For the installation, I used tape and cardboard. I attached the motion sensor to the wall at the height of my dog and the servo to the light switch. Final Product.

Code

Code

Servo Servo; 

int motionSensorPin = D16; 

int servoPin = D1;

int ldrPin = A0;

int motion = LOW; 

void setup() {
    
    pinMode(motionSensorPin, INPUT);
    
    Servo.attach(servoPin);
    Servo.write(0);
    
    Serial.begin(9600);
    
    Time.zone(-6);
}

void loop() {
   
    motion = digitalRead(motionSensorPin);
    
    int ldrValue = analogRead(ldrPin);
    
    int currentHour = Time.hour();
    
    
    if (ldrValue < 450 && currentHour >= 16 && motion == HIGH)
    {
      Servo.write(180);  
      delay(50);  
    }
}

Automatic Dog Lightswitch

Things used in this project

Hardware components

Story

Setup

Completion

Schematics

Circut

Code

Code

Credits

Jazlyn Ortiz

Comments

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Automatic Dog Lightswitch

Automatic Dog Lightswitch

Things used in this project

Hardware components

Story

Setup

Completion

Schematics

Circut

Code

Code

Credits

Jazlyn Ortiz

Comments

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