PI Gyro

V0.5

May 2018 - This is no longer being maintained by the original author.

Please feel free to fork, copy, adapt if you find it useable

Using a mobile phone as a Compass / Pitch / Roll sensor to your Raspberry Pi.

Communication: Phone: Home wifi network, Pi: Home network, Internet accessability: yes

Modern javascript (running in a browser on the phone) is entitled to ask the phone for its orientation readings. Not the raw sensor readings, but a higher-level set of yaw (compass heading), pitch (front up/down) and roll (side up/down) figures.

Using an easy "node.js" implementation of a 1-page webserver on the Raspberry Pi, javascript at the Pi can make a socket link with the javascript on the phone, and the Pi can very easily accept a stream of orientation data from the phone. Thus the phone becomes a hand movement controller, like a modern game controller. Use the orientation data at the Pi as input for whatever you need. This demo simply prints the three figures to Pi terminal screen.

Requirements:

• Smartphone. Android was tested. iPhone expected to be similar. The phone just runs a browser.
• Wifi home network with internet. (Internet just to download jquery.)
• Two files for the Raspberry Pi: server.js (the webserver), index.htm (will be fetched by the phone).
• "node.js" aka node - installed on the Pi.
• Three modules downloaded for node: socket.io and node-static and ip

SETUP:

1. Make yourself a working directory and make your project in there. Eg /home/pi/gyro/ It will probably only get the 2 files.

2. NODE.JS: If you install from the Raspbian repository, you get an old version of node.js. Instead get it from http://node-arm.herokuapp.com/ This installed node 0.12.1 for me.

3. MODULES: Use Node Package Manager (which installed as part of node). It doesn't seem to matter whether you load the modules locally or global.

•   npm install socket.io ip node-static
  

4. THE TWO FILES: Get them from github. https://github.com/BLavery/PiGyro The zip file lower right is easiest. unzip into your folder.

5. START WEBSERVER: On the Pi, start webserver. Run in a terminal:

•   node server.js
  

6. PHONE: Start browser. Set address to the Raspberry Pi address on your network, at "port 8080". Eg: http://192.168.1.14:8080 Press OK to start. That's it! Move the phone. Changing sensor figures should print on the Pi.

Concept credit: https://github.com/shaunuk/picar

Other ref: http://www.w3.org/TR/orientation-event/