This was a quick experiment to see how involved it would be get a Node.js web server to run on a Raspberry PI and communicate with an Arduino over Serial.

One weekend I was playing around with some shift registers to drive a bank of LEDs and thought it'd be cool if I could control them with some kind of UI.

I had a couple of Raspberry PIs lying around so I decided to see if I could get Node.js to run on one of them and serve a simple web page that would accept commands and pipe them out over Serial.

I remember it took over two hours to build Node from source on 700mhz Model A PI but once I was able to bring the server up it was trivial to setup a simple UI and communication bridge.

When the UI loads it generates a random number in JavaScript which is sent to the Arduino and displayed on the seven segment display. This allows the user to know they have successfully connected and can start interacting with the LEDs.