Exchanging messages between two or more Arduino boards can be easily done using a tool called shiftr.io.

Shiftr.io is a MQTT broker which also has a nice graphical interface to monitor that your messages are actually being transmitted across your devices.

MQTT is a internet protocol intended easily connect IoT devices together.

The protocol can run on low power hardware like Arduinos as well as on computer and it It has been implemented in many programming languages.

Simple MQTT use cases:

• One Arduino sends some data to one (or many) other Arduinos via an Internet connection.
• You want to send some data from Arduino to a p5.js or max msp program (or vice versa) via a wireless connection.

NOTES: With MQTT you can only transfer data between nodes. If you need to store or save those data you will have to implement the saving mechanism yourself.

You can use this guide to get started connecting your arduino board to shiftr.io

Arduino

This code will allow you to connect to shiftr.io and start sending messages.

https://create.arduino.cc/editor/lorenzoromagnoli/8cb34f83-a94e-471d-8e36-0e65a5abcfd9/preview?embed

You will then be able to see the transmitted data here

lorenzo/ITD