HTTP Web Client

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Welcome to the “HTTP Web Client” tutorial using the CONTROLLINO MICRO. In this tutorial, we will learn how to create a web client that connects to a web server, using the provided example code as a starting point.


  • Installed Arduino IDE.

Example Code

Please grab the following example .ino file from Github:

Step-by-Step Guide

Step 1: Setup the Arduino Environment

  1. Connect your MICRO to your computer.
  2. Open the Arduino IDE.
  3. Ensure that the appropriate board and port are selected in the Tools menu.

Step 2: Understanding the Code

The example code can be broken down into several key parts:


  • MAC Address: A unique identifier for your network interface. You can use the provided address.
  • IP and DNS: Optionally, you can set a static IP and DNS server address if DHCP fails.

Setup Function

  • Start Serial Communication: Initialize serial communication for debugging.
  • Initialize Ethernet: Attempt to start Ethernet with DHCP. If it fails, it uses the static IP set earlier.

Loop Function

  • Handle Incoming Data: If data is received from the Ethernet, it is printed to the serial monitor for debugging.
  • Reconnect and Send Requests: Every 10 seconds (as set by postingInterval), the httpRequest function is called to send a new request.

HTTP Request Function

  • Connect to Server: Attempt to connect to the specified server on port 80.
  • Send HTTP Request: If the connection is successful, send an HTTP GET request.
  • Handle Failed Connection: If the connection fails, print an error message.

Step 3: Create the Web Client

  1. Modify the MAC Address: Change the mac[] array if you want to use a different MAC address.
  2. Set IP and DNS (Optional): Modify ip and myDns if you need to use a static IP and DNS.
  3. Change Server Address: Replace server[] with the address of the web server you want to connect to.
  4. Upload Code: Connect your CONTROLLINO MICRO to your computer, select the appropriate board and port in the Arduino IDE, and upload the code.
  5. Monitor Output: Open the Serial Monitor in the Arduino IDE to see debug output and responses from the server.


You now have a basic web client running on your CONTROLLINO MICRO. This client connects to a specified web server, sends an HTTP GET request, and prints the response. You can expand on this by modifying the request, handling different types of responses, or integrating this functionality into a larger project.

Remember, networking can sometimes be tricky, so don’t hesitate to experiment and troubleshoot as needed. Enjoy exploring the capabilities of your CONTROLLINO MICRO!

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