15. IoT Case 06: Weather Station

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15.1. Goal

Make a weather station which gets the values from the raindrop sensor, temperature and humidity sensor. The data will be sent to IoT platform - ThingSpeak.

15.2. Background

What is Thingspeak?

ThingSpeak is an IoT analytics platform service which provides instant visualizations of data posted by your devices to ThingSpeak. In this case, we will use this platform to update our data to plot instant graphs.

Weather station operation

Collecting temperature, humidity and raindrop consistently and uploading the data by using Thingspeak. This can help us to do analytical work more conveniently as we can refer to the automatically plotted graphs.

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15.3. Part List

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15.4. Assembly step

Step 1

Attach the raindrop sensor to F2 model.

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Step 2

Attach the temperature and humidity sensor to F2 model. auto_fit

Step 3

Put together all the cardboard parts (F1-F2). auto_fit

Step 4

Assembly completed! pic_60

15.5. Hardware connect

Connect the Raindrop Sensor to P0 port of IoT:bit

Connect the Temperature and humidity Sensor to P2 port of IoT:bit

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Pull the buzzer switch ‘up’ to disconnect the buzzer in this execrise

15.6. IoT (ThingSpeak)

* For more details, please refer to Chapter 1: Upload Data to ThingSpeak

Step 1

Go to https://thingspeak.com, Choose Channels -> My Channels -> New Channel

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Step 2

Input Channel name, Field1 and Field2 , then click “Save Channel”

  • Channel name: Smart Weather Station

  • Field 1: temperature

  • Field 2: humidity

  • Freld 3: raindrop

Step 3

Select your channel > “API Keys” ，copy the API key as follows:

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15.7. Programming (MakeCode)

Step 1. Initialize OLED, IoT:bit and connect to WiFi

  • Snap Initialize OLED with width:128, height: 64 to on start

  • Snap Initialize IoT:bit TX P16 RX P8 from IoT:bit to on start

  • Snap Set Wi-Fi to ssid pwd from IoT:bit

  • Enter your Wi-Fi name and password. Here we set smarthon as SSID and 12345678 as password

  • Set variable raindrop, humidity and temperature to 0 from variables*
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Step 2. Show icon “tick” after WiFi connection

  • Snap show icon from basic to On WiFi connected and select icon tick auto_fit

Step 3. Get temperature, humidity and raindrop values

  • Snap if statement to block forever

  • If WiFi is connected

  • Then, set humidity to read humidity from DHT11 at Pin P2

  • Set temperature to read temperature from DHT11

  • Set raindrop to get raindrop value (percentage) at Pin P0 auto_fit

Step 4. Show values on OLED

  • Snap clear OLED display from OLED to avoid overlap

  • Snap show string and show value of variables Temperature, Humidity and Raindrop auto_fit

Step 5. Upload data to ThingSpeak

  • Snap Send Thingspeak key... inside the if-statement

  • Fill in the api key from Thingspeak with temperature, humidity and raindrop value

  • Snap pause to the loop to wait 15 second auto_fit

Step 6. Show ThingSpeak upload status

  • Snap show string inside On Thingspeak Uploaded

  • Draw the variable Status and Error_code to block show string auto_fit

Full Solution

MakeCode: https://makecode.microbit.org/_TMyYxL8Re1du

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15.8. Result

When micro:bit is connected to WiFi, it will check weather information (temperature, humidity from Temperature and humidity Sensor and raindrop value from raindrop sensor). Then, those data will be sent to ThingSpeak and pause for 15 seconds for another update.

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We can find three graphs on Thingspeak including temperature, humidity and raindrop (field1, field2, field3) respectively by collecting data using different sensors.

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15.9. Think

Q1. How can we upload other module values (e.g. noise) to ThingSpeak?