Getting sensor data from an Arduino and sending it over the Internet to display the data in a graph can be a rather challenging task. This task is made extremely easy when using a IoT (Internet of Things) web service instead of setting up the Arduino to host a web page that contains the sensor data graph. Any Arduino board that has Ethernet on it or any Arduino board with an Ethernet shield can be used to make an Arduino Internet graph.
Arduino Internet Graph
An Arduino Internet graph can easily be made by using the ThingSpeak platform to do all the hard work like capturing the sensor data and plotting it to a graph. The image below shows Arduino analog pin A0 voltage plotted on a graph that is displayed in an account on the ThingSpeak website.
How it Works
A ThingSpeak library is installed in the Arduino IDE using the Arduino library manager. The library provides functions that can be used to communicate with the ThingSpeak web server.
A free account can be opened on the ThingSpeak website which allows channels to be created. Data from the Arduino, which can be sensor data, voltage, or any other data, can then be sent to the channel and plotted on a graph at the website. Each channel can have up to eight fields, enabling data from up to eight sensors to be sent over one channel.
When using ThingSpeak, no SD card is needed and the Arduino and Ethernet shield or other Arduino board that has Internet capabilities is set up as a client rather than a server. No special Internet router settings need to be made when the Arduino is used as an Internet client, making setup and use very easy.
Arduino Internet Graph Plotting Tutorial
A full tutorial on how to plot sensor data over the Internet with Arduino is available in the article Logging Data and Displaying Graphs over the Internet with Arduino.