Display Graph on Website
(Raspberry Pi)

In this project, you will improve your previous website and display a graph showing data from a Humidity Phidget!


Before getting started, make sure you have the following parts.

Getting Started Kit

Any Raspberry Pi

Step 1

Simply connect your Getting Started Kit to your Raspberry Pi. Note: make sure your Humidity Phidget is connected (not shown in image).

If you haven't set up your Raspberry Pi with Phidgets yet, visit this project.


In the previous two projects, you did the following:

  1. Installed a web server on your Raspberry Pi and modified your website.
  2. Created a Python script that logged data to a file and then displayed that data on your website.

If you have not completed the previous projects, check them out now: Project 1, Project 2

Creating a Graph for Your Website

In the previous project, you logged sensor data to a CSV file. You can now use a graphing library to display the contents of that file on your website. There are many options available online, but for this project, plotly will be used.

Modify Your Website

Overwrite your index.html file with the following:

<!doctype html>
<html lang="en">
        <meta charset="utf-8">
        <script src='https://cdn.plot.ly/plotly-2.14.0.min.js'></script>
        //This is where you will store your temperature data
        var temperature_trace = {
            x: [],
            y: [],
            mode: 'lines+markers'

        function connectPhidgets(){
            temperature_trace.x = [] //reset data
            temperature_trace.y = [] //reset data
            temperatureData = 0 //reset data
                .then(response => response.text())
                .then(text => {
                    let data = text.split("\n");                                        
                    //Get Data				
                    for (let i = 1; i < data.length - 1; i += 1) { 
                        temperatureData = data[i].split(","); 
                        temperature_trace.y.push(temperatureData[0]) //If you have multiple columns, use [1],[2], etc. to access them
                    document.getElementById("dataLabel").innerHTML = temperatureData[0] + "°C"; //display last data point

                    //Plot data
                    var plotly_data = [temperature_trace];
                    var layout = {
                        title: 'Temperature Data',
                        xaxis: {
                            title: 'Num Points'
                        yaxis: {
                            title: 'Degrees Celsius'
                    Plotly.newPlot('dataGraph', plotly_data, layout);                    
    <body onload="connectPhidgets()">
            <h1>Phidget Data</h1>
            <h2 id="dataLabel">?</h2>
            <div id="dataGraph">

What are Phidgets?

Phidgets are programmable USB sensors. Simply plug in your sensor, write code in your favorite language and go!

Phidgets have been used by STEM professionals for over 20 years and are now available to students.

Learn more

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