Hands-On Robotics with JavaScript

Getting the bar graph to update

Remove the console.log() line from the lightSensor.on('change') handler and replace it with:

lightGraph.update(this.value)

Then you're ready to roll! Move the project folder over to the Pi, navigate to the folder in your Pi SSH session, and run:

npm i

To make sure that barcli is properly installed on the Pi, run the command:

sudo node light-sensor-barcli.js

You should see a bar graph now, shown as follows, that changes when you shine light on or cover the sensor:

Now, for our night-light project, you'll want to find a value for the light sensor that we will use to turn the LED on and off; barcli makes this much ...