In this chapter, we are going to create something really similar to what we did in Chapter 2, Sending Data to a Web Server, that is measuring data from a sensor, storing the data, and sending it back to a web server so that it can be plotted.

However, things are going to be similar only on the appearance front. Instead of having an Ethernet client that runs on the Arduino board and sends data to a server, we are going to make the Arduino board more independent. In the first part of the chapter, we are going to log the data locally using the integrated MicroSD card reader of the Ethernet shield.

Then, we are going to create a server right on the Arduino board. The board will measure data as usual, but the server will serve the data to the incoming clients. Finally, we will use a modified version of the code we used in the Chapter 2, Sending Data to a Web Server, to plot the measured data on your computer.

The following will be the major takeaways of this chapter...