Team PetersonParkingSwaglerSensors IOT18:

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Clay Peterson

Published November 12, 2018

MEGR 3171 IOT Parking Sensor

Device that alerts you to stop and turns on a "porch light" when you pull into your parking spot.

IntermediateFull instructions provided4 hours1,226

Things used in this project

Hardware components

Particle Photon

Male/Male Jumper Wires

Ultrasonic Sensor - HC-SR04 (Generic)

Relay Module

5 mm LED: Red

5 mm LED: Yellow

5 mm LED: Green

Resistor 221 ohm

Home-made LED pannel

Software apps and online services

Google Sheets

IFTTT Maker service

Story

This project is a parking spot sensor that alerts you when you are completely in the spot. It will also turn on a light that will allow you to see outside the car at night. Our set up uses two photons that send data back and forth in order to accomplish their tasks.

MEGR 3171 IOT 18: Parking Sensor Project

Photon one will first detect a distance using a HC-SR04 ultrasonic distance sensor. In the software, it will convert this distance that is originally in time of flight to inches. It will then check this distance variable against three sets of distance ranges. Based on the range it is in, it will turn on the appropriate LED - red, yellow, or green.

1 / 3 • Parking Light Tree

Once the distance is inside the red range it will publish an event to the particle cloud. Based on this event, Photon two will run its specified actions described below. Photon one also subscribes to an event published by Photon two. On the receipt of this event, it will turn all on all three LEDs for 5 seconds.

Message received back from light photon so all lights illuminate

This lets the user know who is parking that the LED porch light has been activated and the Photons are both successfully publishing and subscribing to each other - two way communication. Lastly, code has been added that will check for a distance change so Photon one does not continue to illuminate the red LED when parked and continue to send events to the particle cloud. This is implemented as a power-saving initiative due to using an external battery pack.

Circuit diagram for Photon 1 (Distance Sensor)

Photon two turns on the LED light and sends a notification for the graphing aspect. This notification also allows Photon 1 to know when to flash the light tree and then turn off. In the circuit diagram below the 3 LEDs represent the homemade LED array. A lamp or overhead light could used instead of the led array. This new light and its power source would have to be wired into the relay. This project utilizes the 3 AAA batteries that were included with the LED flashlights found at Walmart. These 3 LED boards harvested from the flashlights have built in resistors so no additional circuity is required..

Circuit Diagram for Photon 2 (Porch Light)

After removing the LED boards and the battery packs, we 3D printed a mount and installed the boards. The boards were then wired together in parallel. This array was then connected into the relay. The relay was included into the circuit to allow for use with separate photon light power sources. This also allows for easy conversion to lamps with 120V AC sources. The photon will, when told to, turn on pin D7 which will then activate the relay and turn on the light array. Refer to the Photon 2 code for its explanations in the comments.

When the a publish from Photon two appears in the cloud, IFTTT pulls the data and graphs it into a google sheet. We used the data of "1" and the date to graph. The "1" is repeated as a counter for the sheet. The graph shown below is some of the test data that we collected. It added up the number of times a vehicle parked in the spot for each day.

Live Google Sheet

Link to our live Google Sheet:

https://docs.google.com/spreadsheets/d/1n__sn8Me-0os2vfDoO6Zf4uHfEwxwfhlKH7dlLiBlpw/edit?usp=sharing

IFTTT:

Below are the steps for the IFTTT set up.

1) Make an account at https://ifttt.com/discover

2) Navigate to my applets, new applet, build on the platform

3) Fill in the relevant personal information and then click applets, new applet.

4) Fill in the information in the below photos

The Event Values where "ingredients" are added add the date and time to the live updating Google Spreadsheet. The code allows the inputting of the date and time in separate columns, rather into a single column. This allows more fine tuning if more data is wanted to be graphed. It also inputs the event contents data.

Log into and give permissions as required for the particle photon

1 / 5 • IFTTT Setup

Schematics

Code

//Photon 2, Turns on the LED porch light and sends a publish that IFTTT will
//pick up and that Photon 2 will pick up to flash the light tree

void setup() {
pinMode(D7,OUTPUT); //Setting up which pin will be used for the output
digitalWrite(D7,LOW);//Setting the default state of the pin to low/off
Particle.subscribe("StevenSwaglerLED", HI, "42002d001051363036373538");
//setting up the subscribe to search for the first photon and then search
//for the publish of StevenSwaglerLED
}
void HI(const char *event, const char *data)
//if the event HI occurs (StevenSwaglerLED is published and found)
//then it will turn on/ turn to high the D7 pin output
{digitalWrite(D7,HIGH);
//The next line of code published an event ClayPetersonLED 
//with the data of "1" for the spreadsheet. "1" is light on nothing is light off
Particle.publish("ClayPetersonLED","1");
delay(60000); //Time the light should be on. The next line turns the D7 pin off
digitalWrite(D7,LOW);
Particle.publish("ClayPetersonLED","0"); //to publish only to spreadsheet 
//(since data on listening photons only run if data == 1)
}
void loop() {
    

}

//Defining variables
unsigned long duration, inch, setdistance, setdistanceinch, diff;
int trigPin = 2;
int redPin = 3;
int yellowPin = 4;
int greenPin = 5;
int echoPin = 6;

void setup()
{
    //Defining inputs and outputs
    pinMode(redPin, OUTPUT);
    pinMode(yellowPin, OUTPUT);
    pinMode(greenPin, OUTPUT);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    pinMode(D7, OUTPUT);
    Particle.subscribe("ClayPetersonLED",LEDOn,"4b0023000351353530373132");
    setdistanceinch = 0;
    Serial.begin(9600);
}

void loop()
{
    delay(10); //lines 23 - 30 output and collect the soundwave, get a duration in
    //terms of microseconds, convert that time to distance since we know how fast sound travels
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW); 
    duration = pulseIn(echoPin, HIGH);
    inch = (duration/2) / 74; //divides time in half since wave has to go both there and back,
    //divides by 74 since that is the time it takes for sound to travel one inch.
    diff = (abs(inch - setdistanceinch)); //This will gather a change in distance from when the
    //red light zone was last activated so we can determine if the car is parked or not. This is
    //absolute to solve the problem of it losing the distance right when it takes the setdistance
    //measurement and the setdistance being 10+ feet away
    
    if (diff >= 4 && inch <= 1000){ //only runs if car has moved four inches since last in the red 
    //light zone and is closer than 7 feet
    setdistanceinch = 0; //redefine our set distance to zero so we can move into red zone if the 
    //setdistance was previously set to 20-24 inches
        
        if (inch > 60){ // if greater than 5 feet, turn on green light
            digitalWrite(greenPin, HIGH);  
            delay(200);
            digitalWrite(greenPin, LOW);
        }
        else if (inch > 24 && inch <= 60){ //if greater than 2 feet but less than or equal to 5 feet, 
        //turn on yellow light
            digitalWrite(yellowPin, HIGH);  
            delay(200);
            digitalWrite(yellowPin, LOW);
        }
        else if (inch <= 24){ //if less than 2 feet, turn on red light, publish an event so LED photon
        //can see we are in red zone, and define a setdistance where we are parked.
            Particle.publish("StevenSwaglerLED", "1");
            digitalWrite(redPin, HIGH);  
            delay(5000); //delay 5 seconds to allow the driver to park in the red zone before capturing
            //parking distance (set distance)
            digitalWrite(redPin, LOW);
            setdistanceinch = inch; //defines parked distance so we must change from this (EITHER direction) 
            //4 inches before lighting code will run again.
        }    
    }
    else{
       delay(500); //delay half second when outside of 7 foot range
    }
    
}

    
void LEDOn(const char *event, const char *data) //turns all lights on tree on for 5 seconds after
//receiving event that LED has turned on
{
    if (strcmp(data,"1")==0){
    delay(5000); //must be same as line 49
    digitalWrite(greenPin, HIGH);
    digitalWrite(yellowPin, HIGH);
    digitalWrite(redPin, HIGH);
    delay(10000); //turns lights off and waits 10 seconds before going back to check again
    digitalWrite(greenPin, LOW);
    digitalWrite(yellowPin, LOW);
    digitalWrite(redPin, LOW);
    }
    else{
    }
    
}