This is a small C library libplhm to encapsulate communication with
Polhemus motion tracking devices. These devices communicate with a
computer using a USB serial port or RS232 port. Included is a small
program plhm which can be used to request data from the device, and
record this to a file or send it across the network using the Open
Sound Control protocol.
We needed such a program to record motion tracking data during experimental sessions in our lab for studying musical gesture, and for communicating with Max/MSP and Pure Data to interact with real-time sound synthesis. The result is this small driver that can be used for any purpose.
The protocol has been derived from documentation from Polhemus, available in the Liberty Manual
Run plhm --help to get information on usage.
The Polhemus USB interface can be used under Linux by loading the
visor kernel module with the appropriate vendor and product
identifiers:
modprobe visor vendor=0x0f44 product=0xff12
This should make the device show up as a USB serial device, ttyUSB0.
If you wish to use a different device, pass the -d option to plhm.
Ensure you have permission to read and write the device. For example,
$ ls -l /dev/ttyUSB0
crw-rw---- 1 root dialout 4, 64 2009-11-18 15:43 /dev/ttyUSB0
This indicates that your user must be in the dialout group before
running plhm.
Note that plhm can be run in the daemon mode (option -D). This
makes plhm wait until the device is available, and then opens it and
allows control of the device using Open Sound Control. We use this
mode in our lab, executed by a boot script on the dedicated headless
computer. This allows us to treat the computer and device as an
OSC-controlled "appliance", interacting over the network with
Max/MSP.
Currently the library does not cover the full functionality of the tracker. It has also been only tested on an 8-station Polhemus Liberty device, and may require some small modifications for the Patriot device. It is currently a Linux-only program.
Please feel free to add functionality, make suggestions, or submit testing reports on other equipment.
This program uses the autotools build system. A normal install process consists of the following steps:
./configure
make
make install
See INSTALL for further instructions.
This library has primarily been authored by Stephen Sinclair, in the Input Devices and Music Interaction Lab at McGill University. It is based on previous code by Mark Mashall, with some small contributions from Mike Collicut.
The homepage for this program can be found at idmil.org, and the source is also available on github.
Please report any bugs to Stephen at sinclair@music.mcgill.ca.
This code is licensed under the GNU General Public License v2 or later. Please see COPYING for more information.