CNMAT Flashback

A look back at some items in our archives.

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Book page

Half-round, Piezoresistive Fabric, Conductive Heatshrink and Copper Tape

[inline-left:Figure4.jpg]The previous designs are limited by the sizes of floor protecting
disks available. This construction is free
of these size constraints.

A half-round wooden strip is cut to the desired length and two
separate strips of copper tape are employed on the flat length
and the curve. A strip of piezoresistive fabric is trapped and

Book page

E-field (Capacitive) Sensing Foot Switch

The previous examples use the same physical sensing
principle: gesture modulating current flow. Capacitive or e-field
proximity sensing is an interesting alternative principle to apply
for rapid prototyping. Only one conductor is needed and more
flexibility about where the conductor is placed is available. It
can be under glass, plastic or wood or other non-conducting
material.

Book page

Position Sensing Trip and Rubber Door Threshhold

To create multiple foot switches we can simply tile out arrays
of the previously described devices. There is a better, faster
way with the additional convenience that the switch functions
are built into a single strip that is constructed quickly in a few
steps. Instead of employing the principal of piezoresistivity
change we employ a printed-resistor position-sensing strip such

Book page

Building Foot-Switches with Fiber, Fabric and Other Malleable Materials

A simple gestural controller indeed, but the humble footswitch finds
wide use in technology-based musical performance contexts
because the performer’s hands are usually actively engaged
playing an instrument.

The traditional approach is to mount a
heavy-duty mechanical switch into a solid metal box. These
“stomp boxes” are standard tools of the electric guitarist. As a

Book page

OSC Address Schema

The OSC address schema of micro-OSC is broken down into a number of modules. Not all modules may be present depending on the hardware support and compile-configuration. Some addresses may change in the future--this document will be updated to reflect the current state of the OSC message address schema.

Book page

Status LED

Enables control over on-board status lights.

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**/status/0** : Get/set status light state

Some boards have more status lights, which are numbered /0 /1, etc.

Understands "on", "off", 0, 1.

TX: [ /status/0 ]
RX: [ /status/0 ,i 0 ]
TX: [ /status/0 ,s "on" ]
RX: [ /status/0 ,i 1 ]

Book page

Profile

The profiling system is enabled by a compile-time switch.

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**/profile/** : Reports timer measurements made over various sections of code.

These messages are reported approximately once per second.

Book page

Device

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**/device/id** : Get/set device identification string.

The identification string is an ASCII character sequence, limited to 8 characters in length. It is automatically populated with a random-number on first startup. The device ID is also reported as the "serial number string" in the USB descriptor, but you will need to restart the device for this to be updated.

Book page

EEPROM

The EEPROM module is an experimental module, mainly of interest to developers. It interfaces directly to the EEPROM at the byte level. Presently only the first 64 bytes are in use by micro-OSC, and the current platforms have 256, however more space may be required in the future.

Book page

Terms of Use

The following copyright notice and terms of use apply to the micro-OSC firmware, its source code, and other supporting software distributed by CNMAT:

Copyright © 2008 The Regents of the University of California (Regents). All Rights Reserved.

Book page

OSC over the USB-Serial Transport

# Overview

A serial port is a bidirectional point-to-point communications channel. Open Sound Control is a datagram protocol which means that it requires a packetized transport (UDP is a common example of this). Serial isn't a packetized transport (nor is, for example, TCP).

# The SLIP framing protocol

Book page

USB Descriptor and Device Identification

Here is an overview of the micro-OSC device descriptor.

The VendorID/ProductID used is by permission from Microchip Technology Inc. under a sublicense agreement. This VID/PID may only be used with Microchip products.

Book page

Known Bugs and Possible Issues

- Sometimes the device does not seem to receive commands to toggle the status lights. After resetting uOSC, it works again.
- USB Prober only seems to work correctly before the serial port is activated. Suspect the control endpoint isn't getting serviced because it is starved by activity on the CDC data endpoint.

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