Voyager-bot

A cam-streaming carbot controlling from a web browser using Nodejs with Raspberry pi and Arduino.

Hardware

• Raspberry pi
  • Camera board
  • Usb Wifi dongle
• Arduino
  • DC Motors
  • H bridge
  • Sensors

Software dependencies

• Firmata (Arduino)
• Nodejs
  • Jhonny-five
  • Socket.io

Getting started

The first thing we need to do is flash an Arduino board with the Firmata protocol. For this "experiment" we use a modified sketch for the Firmata that's woks well with proximity sensors and servo.

In src/sketch.ino is the file ready for upload to the board. To archive this yo can use the ino command line tool.

Install the Arduino IDE

Yo can installed with yum or apt-get.

$ yum install arduino

Install picocom

The picocom command line tool will helps us with serial communication.

$ wget https://picocom.googlecode.com/files/picocom-1.7.tar.gz
$ tar -xvzf picocom-1.7.tar.gz
$ cd picocom-1.7
$ sudo make
$ sudo make install

Once you installed all the dependencies above, install ino using pip or easy_install

$ pip install ino

Setting up your board

Edit the file ino.ini with the specs of your board and the serial port.

[build]
board-model = mega2560

[upload]
board-model = mega2560
serial-port = /dev/ttyACM0

[serial]
serial-port = /dev/ttyACM0

Installing the Firmata protocol

Build the file in src/sketch.ino

$ ino build

Upload

$ ino upload

Installing the node modules

The Arduino board is ready now to use Nodejs with Jhonny-five. Make sure you have the latest build of nodejs and npm in the Raspberry pi.

$ npm install

Connect the arduino to the rpi then run:

$ node app.js

You should see this:

Controlling from a web browser

Setup a static http server in app.js

app.listen(8000, function () {
    console.log('Http server listening on port %d', 8000);
});

That will serve the index.html which hold the Socket client.

For handle browser events we use jQuery and keypress in order to detect when a key is pressed then and do a socket emit.

"keys": "up",
"on_keydown": function() {
    console.log("Client: Going forward");
    socket.emit('goForward');

From the server side we listen to the emit usingsocket on

socket.on('goForward', function(){
    console.log("Server: Going forward! ");
    // Do something
});

Running in a Docker container

Containers are a really good idea for Iot projects because we can isolate our app on a kernel level and that means portability across machines, rapid application deployment, those are crucial processes for Iot projects.

But Docker, which is a de facto standard, does not support ARM. So it is not yet support for Raspberry pi, fortunately some hackers make a Docker Image for Raspberry Pi, they called Hypriot.

Install Hypriot in your Raspberry pi. See this guide

Now login into your pi.

Get the repo

$ git clone https://github.com/juliocesar-io/voyager-bot.git

cd voyager-bot

Build the image

$ docker build -t <your_tag_name> .

Connect the Arduino(Flashed with Firmata) to the Raspberry pi.

Run the container

$ docker run --device=/dev/ttyACM0 <your_tag_name>

Notice that we flag the --device=/dev/ttyACM0 it's important to define this, it won't work if you don't use the correct port, check it with lsusb.

See the result in your browser, http://<container_ip>:3000