Conducting with a Geared Gametrak

Series: alt.ctrl activities; builds on Gametrak; Spatial arrangement

The Gametrak measures inside a cone: the longer the tether, the larger the space it covers and the less precisely it measures. So use the shortest tether that covers the gesture, and let players choose their range of motion as they play, with the tether's length acting as a gear.

Materials

Item	Amazon	eBay
A Gametrak controller (originally sold with two gloves and a footswitch)		search
A sturdy music stand
A computer with Max/MSP or Pd

Tools

Tools not yet listed.

Skills

Skills not yet listed.

Instructions

Set the Gametrak up as in Set Up a Gametrak for Music.
Install the Gametrak at waist height in front of the conductor, for example on a sturdy music stand.
Attach the conducting hand to a tether, for example with a Gametrak glove.
Map the tether's angles to an analysis of the conductor's rhythmic gestures.
Use the tether's length as the gear: scale the angles by it, so that a conductor who stands back and uses space flamboyantly and one who stands close with small, precise gestures both cover the full range.
Keep the length reading in the analysis too: it can give the direction of the conductor's leaning gestures.

Variations

Variations not yet written.

Related resources

Musical Applications and Design Techniques for the Gametrak Tethered Spatial Position Controller, Freed and others, SMC 2009, section 4.5

Coding Prompt Build Block

A prompt to give a coding assistant, to start the code for this activity. Copy the box, answer its questions about your board and pins, and test what comes back on the bench before you rely on it.

I am building "Conducting with a Geared Gametrak", the activity at https://adrianfreed.com/gametrak-gearing-conducting.html.

Write a Max or Pd patch, or a program, for a Gametrak at waist height in front of a conductor, with the conducting hand on a tether. Scale the tether's angles by its length, so that a conductor who stands back with large gestures and one who stands close with small, precise ones both cover the full range.

Analyse the scaled angles for the conductor's rhythmic gestures: the beats and their timing. Keep the length reading in the analysis too: it can give the direction of the conductor's leaning gestures.

Libraries to explore:

o.io.gametrak (CNMAT MMJ Depot): CNMAT's Max patch for the Gametrak: it opens the device and outputs /left/x, /left/y, /left/z, /right/x, /right/y, /right/z and /footswitch, the angles scaled from -1 to 1 and the extensions from 0 to 1 (https://github.com/CNMAT/CNMAT-MMJ-Depot/tree/master/patchers/io/gametrak)
odot (CNMAT): the o. objects for Max and Pd that o.io.gametrak is built from, with OSC bundles as their data type (https://github.com/CNMAT/CNMAT-odot)
Max hi object: reads human interface devices, such as game controllers, in Max (https://docs.cycling74.com/reference/hi/)
Pd hid external: reads USB HID devices, such as joysticks and gamepads, in Pd, on GNU/Linux and macOS (https://github.com/pd-externals/hid)

Before writing anything, ask me what I am using: the board and its pins, or the software (such as Max, Pd or Python), and check its documentation for what this needs. Put the pin numbers, ranges and other settings in one block at the top, each with a comment. Say which of the libraries above you use, and why. Start with a test that shows the raw readings, so that I can check the wiring and the ranges before the rest.

This activity by Adrian Freed is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0): you may share and adapt it with attribution, for non-commercial purposes such as personal projects and teaching, and you must share adaptations under the same licence. Product names and links belong to their suppliers.