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Lesson 48: Weather Monitor with ThingSpeak

This project collects temperature and pressure data using an Atmospheric Pressure Sensor. The collected data is then transmitted to the ThingSpeak cloud platform via an ESP8266 module and Wi-Fi network at regular time intervals.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Universal Maker Sensor Kit	94	Universal Maker Sensor Kit

You can also buy them separately from the links below.

Component Introduction	Purchase Link
Arduino UNO R3 or R4	BUY
Breadboard	BUY
ESP8266 Module	-
Temperature, Humidity & Pressure Sensor (BMP280)	-

Wiring

Configure ThingSpeak

ThingSpeak ™ is an IoT analytics platform service that allows you to aggregate, visualize and analyze live data streams in the cloud. ThingSpeak provides instant visualizations of data posted by your devices to ThingSpeak. With the ability to execute MATLAB® code in ThingSpeak you can perform online analysis and processing of the data as it comes in. ThingSpeak is often used for prototyping and proof of concept IoT systems that require analytics.

1) Creating ThingSpeak Account

The first thing you need to do is to create an account with ThingSpeak. Since the collaboration with MATLAB, you can use your MathWorks credentials to login to ThingSpeak .

If you do not have one, you need to create an account with MathWorks and login to ThingSpeak Application.

2) Creating the channel

After logging in, create a new channel to store the data by going to “Channels” > “My Channels” and clicking on “New Channel”.

For this project, we need to create a channel called “Weather Monitor” with two fields: Field 1 for “Temperature” and Field 2 for “Atmospheric Pressure”.

Code

1. Open the Lesson_48_Iot_Weather_Monitor.ino file under the path of universal-maker-sensor-kit\arduino_uno\Lesson_48_Iot_Weather_Monitor, or copy this code into Arduino IDE.

   Note

   To install the library, use the Arduino Library Manager and search for “Adafruit BMP280” and install it.

2. You need to enter the mySSID and myPWD of the WiFi you are using.

   String mySSID = "your_ssid";     // WiFi SSID
   String myPWD = "your_password";  // WiFi Password
   

3. You also need to modify the myAPI with your ThingSpeak Channel API key.

   String myAPI = "xxxxxxxxxxxx";  // API Key
   

   

   Here you can find your unique API KEY that you must keep private.

4. After selecting the correct board and port, click the Upload button.

5. Open the Serial monitor(set baudrate to 9600) and wait for a prompt such as a successful connection to appear.

   

Code Analysis

1. Initialization and Bluetooth setup

   // Set up Bluetooth module communication
   #include <SoftwareSerial.h>
   const int bluetoothTx = 3;
   const int bluetoothRx = 4;
   SoftwareSerial bleSerial(bluetoothTx, bluetoothRx);
   

   We begin by including the SoftwareSerial library to help us with Bluetooth communication. The Bluetooth module’s TX and RX pins are then defined and associated with pins 3 and 4 on the Arduino. Finally, we initialize the bleSerial object for Bluetooth communication.

2. LED Pin Definitions

   // Pin numbers for each LED
   const int rledPin = 10;  //red
   const int yledPin = 11;  //yellow
   const int gledPin = 12;  //green
   

   Here, we’re defining which Arduino pins our LEDs are connected to. The red LED is on pin 10, yellow on 11, and green on 12.

3. setup() Function

   void setup() {
      pinMode(rledPin, OUTPUT);
      pinMode(yledPin, OUTPUT);
      pinMode(gledPin, OUTPUT);
   
      Serial.begin(9600);
      bleSerial.begin(9600);
   }
   

   In the setup() function, we set the LED pins as OUTPUT. We also start serial communication for both the Bluetooth module and the default serial (connected to the computer) at a baud rate of 9600.

4. Main loop() for Bluetooth Communication

   void loop() {
      while (bleSerial.available() > 0) {
         character = bleSerial.read();
         Serial.println(character);
   
         if (character == 'R') {
            toggleLights(rledPin);
         } else if (character == 'Y') {
            toggleLights(yledPin);
         } else if (character == 'G') {
            toggleLights(gledPin);
         }
      }
   }
   

   Inside our main loop(), we continuously check if data is available from the Bluetooth module. If we receive data, we read the character and display it in the serial monitor. Depending on the character received (R, Y, or G), we toggle the respective LED using the toggleLights() function.

5. Toggle Lights Function

   void toggleLights(int targetLight) {
      digitalWrite(rledPin, LOW);
      digitalWrite(yledPin, LOW);
      digitalWrite(gledPin, LOW);
   
      digitalWrite(targetLight, HIGH);
   }
   

   This function, toggleLights(), turns off all the LEDs first. After ensuring they are all off, it turns on the specified target LED. This ensures that only one LED is on at a time.