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Intention

Today's products and services are aimed at ensuring access to information for all at the tip of their hands through the personal digital assistant devices available. In that regard, in homes and other numerous places (think dorms, suites etc.) where the occupants are not necessarily connected with each other, it will be really beneficial to know whether a particular place is currently occupied or not. My goal is to make this information accessible to people in that particular context so that they can avoid unnecessary effort and also make better, smart decisions in their daily life.

Context

Given that I stay in a home with five other people and we generally ask each other about the availability of other people in our home, I think it will be highly beneficial for all of us, especially to my housemate living on the first floor, who gets asked about all others if this information availability is ensured whenever it is required. Also, it could highly useful in emergency/ urgency scenarios since if we know that the person is not available at home, we can ourselves do the work or call for outside help immediately.

There are a couple of precedent projects related to this one which could be found here:

http://www.instructables.com/id/Make-An-Simple-Motion-Sensor-Light-PIR/

http://ideate.xsead.cmu.edu/uploads/contents/8028/original/homehack.pdf?1486020771

Parts Required

1) Motion Sensor (PIR Sensor)

2) Photon Particle

3) Led

4) Power Source (Battery)

4) Internet connection

5) External application for PDA Integration (IFTTT)

6) Jumper wires

7) Resistor

8) Breadboard

Process

Outline your approach to the project? What ideas did you generate and how did you refine or reject them? What did you research and explore? what were the design choices? What challenges were encountered and how did you resolve them?

Research & Exploration:

The first step in the process was about finding the right sensor out of available ones which would detect the motion as well as be appropriate for this application. Sensors such as hall effect would work only when there is a magnet to activate it which may not be available on all the doors of a home. So, we zeroed in on the PIR sensor which seemed to suit the application as it would trigger a response whenever it detects motion in front of its Fresnel lens.

Design Choices:

- The placement of the product would be at the entrance of each of my housemate's room so that we could continuously keep track of the movement in and out of the room.

- An LED light was also used to let users know that they are being tracked and also to ensure that their privacy is not violated at any cost.

Occupancy Status:

- The important design choice of this project was to correctly note the status of the room occupancy to know whether the person is inside the room or not. So, in this case, it was assumed that the person would be into his room every night by 12 am and a counter was used to keep track of the number of times of trigger in the sensors due to the nature of motion of the person. For example, the counter would be 1 when the person is out of the room for the first time during a new day and the counter would get incremented each time there is a movement into and out of the room from thereon, thus the odd counter values would give output saying the person is OUT of the room and the corresponding even values would give output saying the person is IN to the room again.

External Integration:

The third-party service - IFTTT was used to send notifications to my housemates whenever there is a movement in& out of the rooms/house. Whenever there's an output published in the particle console, it would trigger a push notification to my mobile phone about the occupancy status of the room.

int inputPin = D0;              // choose the input pin (for PIR sensor)
int ledPin = D1;                // LED Pin
int pirState = LOW;             // we start, assuming no motion detected
int val = 0;                    // variable for reading the pin status
int ctr = 0;
int calibrateTime = 10000;      // wait for the thingy to calibrate

void setup()
{ Serial.begin( 9600 );
  pinMode( ledPin, OUTPUT );
  pinMode(inputPin, INPUT);     // declare sensor as input
}

void loop()
{

  // if the sensor is calibrated
  if ( calibrated() )
  {
  // get the data from the sensor
    readTheSensor();

    // report it out, if the state has changed
    reportTheData();
  }
}

void readTheSensor() {
  val = digitalRead(inputPin);
}

bool calibrated() {
  return millis() - calibrateTime > 0;
}

void reportTheData() {

  // if the sensor reads high
  // or there is now motion
  if (val == HIGH) {
    ctr++;
    // the current state is no motion
    // i.e. it's just changed
    // announce this change by publishing an eent
    if(ctr%2 == 1)
    {Particle.publish("OUT");}
    else if(ctr%2 == 0)
    {
      Particle.publish("IN");}
    if (pirState == LOW) {
      // we have just turned on
      // Update the current state
      pirState = HIGH;
      setLED( pirState );
    }
  }
   else {
    if (pirState == HIGH) {
      // we have just turned of
      // Update the current state
      pirState = LOW;
      setLED( pirState );
    }
  }
}
void setLED( int state )
{
  digitalWrite( ledPin, state );
}

Click to Expand

Reflection

Reflect on the process of making this project. What did you learn? What would you do differently?

- PIR sensor has its issues: High sensitivity and a wide range of detection do not allow for smooth and discrete detection of motion as it easily gets triggered due to even a small change in motion (removing your hand after having given an input). Due to this issue, there's a continuous output generation. A possible solution would be to opt for a completely different kind of sensor to detect the motion such as proximity switch or light sensors.

- The product needs to accommodate a wide range of use-case scenarios (multiple rooms, robustness etc.) and designed and packaged well enough to become commercially viable.

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Found In

DIoT 2018 1- Home Hack

Courses

49713 Designing for the Internet of Things

· 25 members
A hands-on introductory course exploring the Internet of Things and connected product experiences.

Focused on

IoT Products

About

We always ask this question to others "Did you see person A around", "Is he in his place" and when it's applied to a home setting, it generally is housemates asking each other whether another of their housemate is in their room or not. In order to help people know that information and also to avoid both the effort and embarrassment of having to walk till their room and intruding them to find out whether they are in or out, my hack aims to let people know through their PDA's, information about who's in the home/ room and who's not.

Created

January 25th, 2018

Made by Gokul Narasimhan Suryamurthy