Published April 9, 2017 © GPL3+

The Light Saver

Tired of your bathroom light being left on? This IoT project turns your light on when motion is detected and back off when you are finished.

BeginnerFull instructions provided3 hours1,169

Things used in this project

Hardware components

Particle Photon

Servos (Tower Pro MG996R)

Jumper wires (generic)

Breadboard (generic)

PIR Motion Sensor (generic)

Software apps and online services

IFTTT Maker service

Story

Introduction

Do you leave your bathroom light on way too much? We do too. That's why we've created a device that senses when you walk into your bathroom and turns the lights on. And you don't even have to worry about turning them off when you're done! The device will turn the lights back off after a specified amount of time, which can easily be set by the user. For the testing of this project, we set the time to turn the lights off after 30 minutes.

Photon Setup

The device uses one Particle Photon with a passive infrared motion sensor to detect when you walk into your bathroom and another Particle Photon with a servo motor and attachment to turn the light switch on and off. The two photons communicate by Particle.publish and Particle.subscribe located in the codes.

Photon 1 with passive infrared motion sensor.

Photon 2 with servo motor and power bank connected.

Servo motor with wooden attachments controlling the light switch.

System Demonstrations

Light Saver system demonstration

Below is a simple video of the servo motor turning the lights on for 5 seconds then back off. Again, the amount of the time the light is on is determined by the user.

IFTTT Event

Using the IFTTT mobile app, we created an applet that sends a notification to the user's phone when the event occurs. Here, the photon named 'kaitlin' published the event 'light' meaning the sensor was triggered and the lights were turned on. This app was used

IFTTT event notification

Not only does the Light Saver significantly prolong the lifetime of the lightbulbs, but also helps cut down on energy costs. Using an IFTTT event, we were able to plot when the lights were turned on through the duration of one day. Shown in the plot below, when the lights were on, there was a value of 1, and when the lights were off there was a value of 0.

The motion sensor was triggered, turning on the lights, eight times throughout the day for 30 minutes each, yielding a total of four hours that the bathroom lights were on. Compared to leaving the lights on all day, as many people do, you can save around $40 a year. This estimation can be seen below.

Cost estimation to run four lightbulbs at 14 W each for 24 hours.

Cost estimation to run four lightbulbs at 14 W each for 4 hours.

Code

Servo myservo;  // create servo object to control a servo
                // a maximum of eight servo objects can be created


int pos = 75;    // variable to store the servo position
int led = D7;


void setup( ) {
    pinMode(led,OUTPUT);
    digitalWrite(led,LOW);
  // attaches the servo on the D0 pin to the servo object
  myservo.attach(D0);

  // register the Spark function

  Particle.subscribe("motion-detected", monkey, "4b0050001451353432393433");
}

void monkey(const char *event, const char *data)
{
     digitalWrite(led,HIGH);
     if (strcmp(data, "light")==0)
     {
myservo.write(115);
delay(1800000);
myservo.write(75);
     }
}


void loop()
{
  
}

Credits

tristan zuber

1 project • 2 followers

uncc

Kaitlin McNeill

1 project • 2 followers

The Light Saver

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Servo Motor Circuit

PIR Motion Sensor Circuit

Code

PIR Motion Sensor

Servo Motor

Credits

tristan zuber

Kaitlin McNeill

Comments

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The Light Saver

The Light Saver

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Servo Motor Circuit

PIR Motion Sensor Circuit

Code

PIR Motion Sensor

Servo Motor

Credits

tristan zuber

Kaitlin McNeill

Comments

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