OVERVIEW

Liberty-Daemon is the daemon process that communicates over USB with the Polhemus High-Speed Liberty motion tracker and reads data from the eight sensors and puts them onto the "liberty" ach channel. The daemon reads position (x, y, z) and rotation (quaternion w, i, j, k).

COMMUNICATION

• Set up for USB (but RS-232 is possible)

PREQUISITES

The following are necessary prerequites to use Liberty:

1. install libusb-1.0.0-dev

   sudo apt-get install libusb-1.0.0-dev

2. install ach (up-to-date instruction are at http://github.com/golems/ach)

• Add the following to /etc/apt/sources.list (substitute the codename for your distribution in place of squeeze, e.g. wheezy, precise):

  deb http://code.golems.org/debian squeeze golems.org

  sudo apt-get update && sudo apt-get install libach-dev ach-utils

  sudo dpkg-reconfigure ach-utils

CLONE THIS REPO

1. Close this Liberty-Daemon repo to your desired location on your computer.

   git clone https://github.com/golems/Liberty-Daemon.git

INSTALLATION

1. go to the Liberty-Daemon directory

   cd Liberty-Daemon

2. compile libertyd.cpp

   make

USAGE (Single computer)

1. create an ach channel called 'liberty' ("-o 666" gives permissions)

   ach -C liberty -o 666

2. run the libertyd executable on the main computer

   sudo ./libertyd

USAGE (Two computers: from main computer to remote computer)

1. create an ach channel on both computers called 'liberty' ("-o 666" gives sudo permissions)

   ach -C liberty -o 666

2. run the libertyd executable on the main computer

   sudo ./libertyd

3. push the data from the liberty channel to the remote computer using "achd" and the ip address of the remote computer

   sudo achd -r push 192.168.1.1 liberty

QUIRKS

• Device takes about ten seconds to initialize after switched on. You must wait this time before starting the daemon.

• The sensor can only measure a positive displacement in X. DO NOT BREAK THE YZ PLANE!

• The daemon does not use Euler angles, and you shouldn't either.