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           /[] _ _\
          _|_o_LII|_
         / | ==== | \
         |_| ==== |_|
          ||" ||  ||
          ||LI  o ||
          ||'----'||
         /__|    |__\

R2D2 Controller

Controller for YesYesNo's R2D2 machine. Runs off of a Raspberry Pi, creates a local webserver that a user can access via their mobile phone to control the direction of the R2 unit.

Installing NodeJS on a Pi

Check this tutorial.

I recommend prebuilt over compiling from source as compilation time is > 2 hours.

Recommended Directory on the Pi

These files can run from anywhere on the Pi but for our purposes we basically copied the source from this repo into the following directory:

~/r2d2

Installing Dependancies

Once NodeJS is installed, you'll need to install all appropriate dependancies run the following commands:

sudo apt-get install libasound2-dev
cd ~/r2d2
/usr/local/bin/npm install

This may take awhile to download and build. As of this writing this application uses the following NodeJS packages:

• node-osc for communicating with... something to play sounds.
• express for serving the web page up.
• socket.io for creating a persistant connection from web page to Pi.
• node-serialport for serial communication to the Arduino
• node-lame and node-speaker for playing sounds (replaced by node-osc)

Running the server

/usr/local/bin/node /home/pi/r2d2/app.js

Then you should be able to hit http://r2d2.local:8080 and see it running.

Command Line Arguments

If testing on a Mac you can say:

node app.js arduinoMode=mac

And this will use a different serial port than the Pi's /dev/ttyACM0. Check the config.js file for more on that.

The config.js file

Most everything in there is pretty straightforward - just paths to hosts and ports and baudrates and what have you.

The web page passes directions as strings that are then sent via serial as characters:

* "forward" becomes "a"
* "backwards" becomes "b"
* etc, etc

These mappings are also in the config.