How to send sensor data to Thingspeak using Raspberry Pi

In some IoT projects data is generated continuously. One way to permanently store them is by saving the data in a local database, however there are other alternatives also available. One of these alternatives is ThingSpeak. Here you can create a free account for small applications and transfer your data very easily. And that’s exactly what this tutorial is about on How to send sensor data to Thingspeak using Raspberry Pi.

Things Needed

For building this project you need below components.

  • Raspberry Pi
  • DHT11 Sensor
  • Jumper Cables

How it works?

The working of this project is simple and easy. DHT11 sensor will collect the temperature and humidity data and send it to Raspberry Pi. Later Raspberry Pi will send it to Thingspeak channel.

how to send sensor data to Thingspeak using Raspberry Pi

Setting Up Thingspeak Account

Before starting, you need a ThingSpeak account. Create an account by clicking on this link here. After creating the account login and click on New Channel to create a channel.

How to send sensor data to Thingspeak using Raspberry Pi

We will define the channels by entering the a proper name, description, and up to 8 fields can be used to name the parameter. For the Field 1 and Field 2 we have named Temperature and humidity. These field values ​​that you set can be modified later. These values will be in Degree Centigrade and Relative Humidity in %. Once you update the name, click on Save.

How to send sensor data to Thingspeak using Raspberry Pi

Once you have saved the channel, you will be automatically redirected to the “Private View” tab. Here the mapped fields are shown as a diagram. You will find the “Channel ID” (we will need it later). Below You will also see API Keys option.

How to send sensor data to Thingspeak using Raspberry Pi

Later, click on the “API Keys” tab. The two values ​​of “Write API key” and “Read API key” are equally necessary for us to write or retrieve data. Copy these keys and keep it safe as we need to put it in the code.

How to send sensor data to Thingspeak using Raspberry Pi

Connection Diagram

This is how you have to make the connection with the sensor to the Pi board. Data or signal pin of DHT11 sensor is connected with GPIO 4 with Raspberry Pi.

How to send sensor data to Thingspeak using Raspberry Pi

Installing Required Libraries

Before installing the libraries we need to update the packages installed in Raspberry Pi. For installing the basic updates run these commands in a terminal window on your Raspberry Pi

sudo apt - get update
sudo apt - get install build - essential python - dev python - openssl git

Now we install the library to read the DHT11  or DHT22 sensors. Below library will work for both the sensor types.

git clone https://github.com/adafruit/Adafruit_Python_DHT.git && cd Adafruit_Python_DHT

We have to run the below command to install Python

sudo python setup.py install

Installing Raspberry Pi Thingspeak Library

In order to use the service, it is possible to simply send the data via “POST” or retrieve it via “GET”. The functions are available in almost any programming language. If you don’t have enough experience or just don’t feel like writing it, you can also use the ThingSpeak library. For this we simply install it using below command

sudo pip install thingspeak
The python script will read the DHT11 temperature and humidity every 15 seconds and send it to our channel.
sudo nano thingspeak_DHT11.py

Inside this new file we will copy this python code

Now Update the code with Channel ID and write key values from Thingspeak portal. Now save it and your code is ready to run.

channel_id = 1391845 # put here the ID of the channel you created before
write_key = 'TNXXJJII892UHJ1C' # update the "WRITE KEY"

Code

If you are using a different GPIO for the sensor apart from GPIO4 then you have to make changes in pin variable in the code. For DHT22 sensor, the code needs to be adjusted a bit more.

You can download the code from the below link and extract it in the root of Raspberry pi directory (/home/pi).

Building and Testing

We have connected the DHT11 sensor with Raspberry Pi as per the connection diagram above. It is also ready with the code to be executed.

How to send sensor data to Thingspeak using Raspberry Pi

For executing the code run the below command in your raspberry pi terminal.

python thingspeak_DHT11.py

Now you will see the output in raspberry pi terminal as well as in Thingspeak dashboard.

In Thingspeak dashboard you can see the graph and the readings.

How to send sensor data to Thingspeak using Raspberry Pi

More Interesting Projects:

DIY Exercise

If you want to build a weather station then you can use the below sensors. You can use the same code but you need to tweak it as per the sensors below. You can do it as a DIY exercise

  • DHT22
  • BMP180
  • LDR

Summary

In this project we are using a DHT11 temperature and humidity sensor with Raspberry Pi. The raspberry pi will connect the values and send it to Thingspeak platform to a particular channel to display the data. We are using python code to run this project. You can enhance this project by adding some more sensors and send the same data to Thingspeak. Hope you like this project and don’t forget to share this article.

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