IoT Team 19:

•

Haleigh Grose

Published November 15, 2020 © GPL3+

MEGR 3171 Lunch Bag Temperature Sensor

With our internet-connected device, you will know if your lunch is safe to eat!

IntermediateFull instructions provided5 hours384

Things used in this project

Hardware components

Breadboard (generic)

ELEGOO 37-in-1 Sensor Module Kit V1.0

Particle Argon

Jumper wires (generic)

Software apps and online services

Particle Build Web IDE

ThingSpeak API

Story

Background:

What we have created is a device that can monitor the temperature inside a food bag or container. The design is super handy as it is connected to the internet, allowing for immediate feedback on the status of your food. This ensures you won't be consuming food that may have gone bad and potentially cause food poisoning. According to the FDA, perishable foods should be stored at temperatures 40 Degrees Fahrenheit or lower. For more information visit: https://www.fda.gov/consumers/consumer-updates/are-you-storing-food-safely.

To protect the components, the temperature sensing configuration should be stored in a sealed, plastic bag when placed inside the lunch bag. This protects the electronic device from spills while still accurately monitoring the status of your tasty snacks. In the video we created for this project (see below), the components of the particle device were not stored in a plastic bag for demonstration purposes only.

We envision our setup being utilized by families and individuals alike. Both kids and adults can be forgetful and leave their lunches outside of a food-safe, refrigerated environment by accident. With our handy, cloud-connected configuration, your mind can be at ease that your family is consuming safe, healthy food!

Please continue reading for more insight into our project setup and execution. Enjoy!

Project Details:

We used a single temperature sensor from an Elegoo Sensor kit for our design. Below is an image of the sensor we utilized for this project.

Elegoo Temperature Sensor

Project Setup:

For our project, we have two Argons that communicate with each other over the cloud using Particle publish and Particle subscribe. To prevent confusion, we have named one Maria's Argon and the other Haleigh's Argon. The two Argons send information back and forth, which is integral to our design set up.

To begin, we wired our circuit and opened the build.particle.io WEB IDE. This is the interface that we used to code our project. Once we had the code finished through trial and error, we were able to communicate back and forth using the Particle.publish and Particle.subscribe. Maria's Argon sent temperature data in an event to Haleigh's Argon, and if the temperature was unsafe, Haleigh's Argon sent an event to Maria's Argon with this information. The D7 light on both Argons would turn on if the temperature data was found to be warmer than a safe food temperature.

To summarize, the completed project works in this manner: the temperature sensor linked with Maria's Argon sends temperature data in the form of events to Haleigh's Argon. If the temperature is below 40 degrees, all is well and no lights turn on. However, if the temperature is above 41 degrees, the blue D7 light, on both Argons turn on, indicating that the food might be at an unsafe temperature to eat.

Data:

Depicted below is our data for temperature versus time. Follow this link to access our real-time temperature data: https://thingspeak.com/channels/1239453.

Thingspeak Data

Below is an image of our circuit for the temperature sensor on Maria's Argon.

Circuit for Maria's Argon

Diagrams for both of the Argon circuits are located in the "Schematics" section. The image of the Particle Argon was originally from https://docs.particle.io/.

YouTube Video

IoT Project YouTube Video

Code

// Maria's Argon Code//

double temperature = 0; // Initalize variable for the temperature data coming f 
int pinvalue = 0; //Initalize variable for the pin input from the temperature sensor

int lunchtemp;

void setup()

{
  
  pinMode(A0, INPUT); // Get input from this pin
  pinMode(D7, OUTPUT); // Set D7 as output
  Particle.subscribe("unsafe", safety, MY_DEVICES); // Subscribe to Haleigh's Particle

 }


    void loop()
    { 
        
      delay(8000); // Delay the loop iterations for eight seconds
    
      pinvalue = analogRead(A0); // Get the value from the A0 pin
      
      temperature = (pinvalue*-.05+107); // Calibrate the input from the sensor 
      
      Particle.publish("temp", String(temperature), PRIVATE); // Publish Temperature data to Haleigh's Argon and Thingspeak
      
    }



void safety(const char *event, const char *data){
    
  String temp = data; // This takes data from the Subscribe and sets it to a new variable name
  
  int  lunchtemp = temp.toInt(); // Changes the string into an integer that the Argon can use
    
    if (lunchtemp < 11){ // Interact with the event being published by Haleigh's Argon. If numbers are less than 11, turn the D7 on
          digitalWrite(D7, HIGH); // Triggered when Haleigh's Particle notes that the lunch is at an unsafe temperature
      }
      else { //Otherwise, the light will be off
      digitalWrite(D7, LOW);
    }
  
 
}

// Haleigh's Argon code //

int temp1;// Initialize a varible for the temperature input from Maria's Argon

void setup() {
    pinMode(D7, OUTPUT); // Set the D7 as an output

    Particle.subscribe("temp", lunchbagtemp, MY_DEVICES); // Subscribe to Maria's Argon event
}
    

void loop() {
    
    if (temp1 <= 40){ //When the temperature is less than 40 degrees, everything is fine so no need to blink the light
       
    }
    
    else if (temp1 >= 41){ //If the temperature is greater than a food-safe temperature, the light comes on
    
        digitalWrite(D7, HIGH); // The light comes on if this is the case
        
        String safety = String(random(5,10)); // Create random numbers to create an event when the D7 light is on
        Particle.publish("unsafe", safety, PRIVATE); // Create a private event that publishes a random number when the light is on
        delay(3000); // Wait three seconds before sending a new event
        
    }
   

}

  void lunchbagtemp(const char *event, const char *data){
    
    String temp = data; // Change the variable data name
    
    temp1 = temp.toInt(); // Change the string into an integer that the Argon can use
 
}

Credits

Maria Adkins

1 project • 1 follower

Haleigh Grose

0 projects • 1 follower

Thanks to Sean Vroom, Gregory Markowski and Daniel Naveira, Kyle McClelland.

MEGR 3171 Lunch Bag Temperature Sensor