IoT with ESP32 board

Creation de avatarSimone Ferrecchia DIGIJEUNES | Categories : Electronics, Machines & Tools, Robotics


In this tutorial you will learn how to connect your ESP32 to the internet and send live values recorded by a light sensor attached to the board, on-line on


1 x ESP32 board + Micro USB cable

1 x light sensor

About 5 jumper wires

1 x 1Kohm resistor


Computer with internet connection and Arduino IDE installed

Step 1 - Set up an account on

Once you have set up an account on, go ahead creating a new Feed. Creat a new feed and name it, for example "lightsensorvalue".

Step 2 - Install Arduino IDE

You can download the software here.

Step 3 - Prepare the ESP32 board on your computer

Follow the instructions provided on github for your OS.

For Windows

If you have troubles following the instructions for windows, you may find some help below

To find the Sketch directory, click File > Preferences, on arduino IDE.

The process of cloning existing repository may take a while...

Step 4 - Check that the board is correctly configured

Launch Arduino IDE

Go to Tools > Board and select  “ESP32 Dev Module”.

Fetch the Blink example on File > Examples > Basics > Blink.

Upload the code by clicking on the arrow pointing to the right, on the top left of the arduino IDE window.

Step 5 - Wiring the photoresistor to the ESP32

The shorter leg of the photoresistor is connected to 3V on the ESP32. The other leg is connected to pin VP (or 36) and at the same time to a 1kohm resistor, which in turn is connected to GND on the ESP32.

Step 6 - Programming on tuniot

On tuniot, we will use the blocks available to create a code for the ESP32.

complete the fields “ssid” and “password” with the name of your wi-fi connection and its password respectively.

The “User Name” and “Key” are available on your account (see image below)

Step 7 - Install Adafruit_MQTT.h and Adafruit_MQTT_Client.h libraries on Arduino IDE

Sketch > Include Library > Manage Libraries…

Step 8 - Programming on Arduino IDE

To upload the code on Arduino IDE, click on the “copy arduino code into clipboard” button

then paste the code onto Arduino IDE, and upload it to the ESP32.

if you click on Serial Monitor (top right of the Arduino IDE screen), you should be able to see the value that is being recorded by the light sensor (see image below).

It means that your ESP32 is connected to the internet, and that it’s sending the value recorded by the photoresistor on-line, on

Notes and references

This tutorial has been developed as part of the I TECH project, co-financed by the Erasmus + program of the European Commission