Published April 26, 2021 © GPL3+

MEGR 3171 Portable Temperature and UV index

This IOT Project provides more accurate temperature and UV index values based on your location vs. what the weather channel could provide.

BeginnerFull instructions provided4 hours41

MEGR 3171 Portable Temperature and UV index

Things used in this project

Hardware components

Particle Argon

DHT11 Temperature & Humidity Sensor (3 pins)

Adafruit veml6070

Jumper wires (generic)

Solderless Breadboard Half Size

USB-A to Micro-USB Cable

Pocket Solder- 60/40 Rosin Core 0.031" diameter

Software apps and online services

Particle Build Web IDE

ThingSpeak API

Hand tools and fabrication machines

Soldering iron (generic)

Story

Our MEGR 3171 IOT Project was motivated by the spring weather and the arrival of summer in the coming months. Living on Lake Norman, the temperature and UV index is important to know when going on the water, and when you are trying to get a golden tan. We used a VEML 6070 UV index sensor and a DHT11 temperature sensor. Using any weather app or local news, you can get the temperature and UV index in the general area, but with our project, more accurate readings can be posted based on your precise location rather than a general area. This makes it easy to check the thingspeak graph on your laptop or phone before heading out on the water. These sensors use IOT technology to bring the solution alive. The wifi connection of the Argon devices is what allows the user to find the Temperature and UV index in their exact location. The sensors will work wherever there is a wifi connection. This is useful in solving the problem of bland, average weather reporting for a large region.

The DHT11 sensor is extremely useful and can output a variety of temperature readings. Our reading was posted in degrees Fahrenheit. The VEML 6070 sensor had to be calibrated. The output of the sensor is the UV light intensity and that has to be divided by a factor to get the UV index. Using a few websites and weather channels, a factor of 210 was settled on to get the UV index from the reading. It is important to note that the UV sensor must be soldered to the included pins for the sensor to work.

Temperature sensor and Joseph's Argon

UV sensor and Brian's Argon

Both Argons together and pre-wired

Measurement set-up outside connected to powerbank

To allow the data to be sent to the cloud and graphed, a thingspeak channel and integration on particle must be created.

The argons use bi-directional communication to send their sensor value to the other argon, and that argon will post the value to thingspeak. This was done to test the communication between the argons. The project can easily be simplified by using one argon. Both sensors can be wired to the argon, and slight editing to the code will have to be done, and both values can be sent by one argon instead of the current setup of two argons. A flowchart of the communication can be seen in the figure below.

Bi-directional communication between Argons

The temperature and UV sensor were set outside for their readings. The temperature was recorded every minute and sent to thingspeak. It was a sunny day, but some clouds were moving in. The incoming cloud cover tells us why the temperature was dropping slightly. During the recording time, various weather sources gave us a temperature in the mid to upper 60s, and a UV index of 4. Both of these were similar to our sensor outputs, but ours may have been more accurate for our exact location. The following graphs show the data. The first graph shows the temperature in Fahrenheit with respect to time.

Temperature graph

The UV index decreased as more cloud coverage approached while the sensors were outside. The UV index value was recorded every 30 seconds to see the impact of changing clouds on the UV value. This second graph shows the UV index value with respect to time.

UV index

The live data from thingspeak can be found here :

https://thingspeak.com/channels/1358252

Here is a youtube video demonstrating our project. The argons are set up, then put outside to gather the temperature and UV index readings.

Youtube video

Code

// This #include statement was automatically added by the Particle IDE.
#include <ThingSpeak.h>

// This #include statement was automatically added by the Particle IDE.
#include <Adafruit_DHT.h>

// This example assumes the sensor to be plugged into CONN2
#define DHTPIN 2     // what pin we're connected to

// Here we define the type of sensor used
#define DHTTYPE DHT11         
int UVint;
DHT dht(DHTPIN, DHTTYPE);

bool humid = false;

TCPClient client;


unsigned long myChannelNumber = 1358252; //Replace with your own channel number
const char * myWriteAPIKey = "1ETUJPTN9B1ZSOYL"; //Replace with your own API key 


void setup() {
    
    ThingSpeak.begin(client);
    
 pinMode(D2, OUTPUT);
 Serial.begin(9600); 
 dht.begin();


}

void loop() {
    // Wait a few seconds between measurements.
    delay(1000);
   
    // Read temperature as Farenheit
    float f = dht.getTempFarenheit();

  String f_string = String(f);
  String UV_string;
  Particle.publish("Temp", f_string , ALL_DEVICES);
  Particle.subscribe("UV",UVdata);
    
    ThingSpeak.setField(2,UVint); // Takes the UV value from argon 2 and it is then posted to thingspeak  
    Serial.print(dht.getTempFarenheit());
    Serial.println("f");
    ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);  
    delay(3000); // ThingSpeak will only accept updates every 15 seconds. 
    
}
 void UVdata(const char *event, String UV_string){

    UVint = String(UV_string).toInt();
}

// This #include statement was automatically added by the Particle IDE.
#include <ThingSpeak.h>

// This #include statement was automatically added by the Particle IDE.
#include <Adafruit_VEML6070.h>

#include <Wire.h>
int fint;
float UV;
Adafruit_VEML6070 uv = Adafruit_VEML6070();

TCPClient client;
unsigned long myChannelNumber = 1358252; //Replace with your own channel number
const char * myWriteAPIKey = "1ETUJPTN9B1ZSOYL"; //Replace with your own API key 

void setup() {
    
     String UV_string = String(UV);
     String f_string;
     Particle.publish("UV_Value",UV_string, ALL_DEVICES);
     Particle.subscribe("Temp",fdata);
     ThingSpeak.begin(client);
     
  Serial.begin(9600);
  Serial.println("VEML6070 Test");
  uv.begin(VEML6070_1_T);  // pass in the integration time constant
}


void loop() {
  Serial.print("UV light level: "); Serial.println(uv.readUV());
  
  delay(1000);
  
    float UV = uv.readUV()/(210);
  
   ThingSpeak.setField(1,fint); //Takes the Temperature value from argon1 and it is then posted to thingspeak 
    Serial.print(uv.readUV());
    Serial.println("uv.readUV");
    ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);  
    delay(3000); // ThingSpeak will only accept updates every 15 seconds. 
    
    
  
}
void fdata(const char *event, String f_string){
    fint = String(f_string).toInt();
}

Credits

Joseph Burgess

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Brian Sullivan

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MEGR 3171 Portable Temperature and UV index

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

Temperature

UV

Code

Temperature

UV Index

Credits

Joseph Burgess

Brian Sullivan

Comments

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MEGR 3171 Portable Temperature and UV index

MEGR 3171 Portable Temperature and UV index

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

Temperature

UV

Code

Temperature

UV Index

Credits

Joseph Burgess

Brian Sullivan

Comments

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