Author: Tom Zicarelli

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Musical stairs

Notes from Gould Academy 2013.

For construction details of the final project see: https://reactivemusic.net/?p=12300

original post

An attempt to collect notes on this project as we bring it to a close.

During Monday’s class I gave students the current version of the Arduino sketch  – and showed them how to hack the code which triggers Midi notes.  it was amazing to see them make changes to the code, which they barely understood – and then upload their changes into the Arduino to see how it affected the sound of the stairs.

There are two sets of stairs:

  • version 1 – built with foam/aluminum foil sensors and a circuit-bent  Radio Shack keyboard. (based on a design from a previous life)
  • version 2 – was done with Arduino, IR emitter/receivers, an Ethernet shield for data logging,

Here are relevant posts – until the student portfolio presentations begin…

Logging data to Pachube

https://reactivemusic.net/?p=4900

https://reactivemusic.net/?p=5163

Arduino IR beam testing

https://reactivemusic.net/?p=4027

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Raspberry-Pi Osc synthesizer

A variation on the Midi synthesizer from this post: https://reactivemusic.net/?p=4960

The synthesizer was built in PureData (Pd extended) using the visual interface on a MacBook. Then the pd file was run in command line mode on the r-pi. The sound card is a Griffin i-Mic, running at 22.5 Khz sample rate. Although there’s no reason why you couldn’t use the builtin DAC on the r-pi.

The r-pi is connected via the ethernet port to a wi-fi network which receives Osc (Open Sound Control) messages from an iPod running touch-Osc. The network connection could have been made using a USB wifi adapter.

All together the cost of this arrangement (less the iPod) would be less than $50. The software is all open source.  The huge financial barriers to working with music synthesis and signal processing, that have been associated with these fields for years, simply don’t exist anymore.

Alternative ways of controlling the synth – if a wiFi router is not available, include:

  • USB keyboard (usually free)
  • USB Midi Keyboard ($25)
  • switches or dials via the GPIO pins (spare parts)
  • direct ethernet connection to another device.
Here is a screenshot of the Pd Patch.

Notes:

Pd file: tkzic/rpi/pd/piSynth1_OSC.pd

recieve port is 8000 – and it uses page 1 of the simple touchOSC template

pd-extended -nogui -noadc  piSynth1_Osc.pd

Note: there is some special code to prevent seg faults when you go from page 2 to page 1 of the touchOSC template

Here’s a great tutorial on using OSC with Pure Data

http://en.flossmanuals.net/pure-data/network-data/osc/

 

 

 

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GPS on Raspberry Pi

Successfully installed this GPS board on the R-Pi.

By Kevin Townsend at adafruit.com

http://learn.adafruit.com/adafruit-ultimate-gps-on-the-raspberry-pi/introduction

The drivers for the console cable were already in the Raspian distribution on the R-Pi.

I installed the gpsd (daemon) software as directed in the above tutorial.

Documentation for gpsd is here:

http://gpsd.berlios.de/client-howto.html

Sample C code is: gpxlogger.c and cgps.c – which can be found in tkzic/rpi/gpsd 3.7/

(todo – write sample code and add to telemetry tracker)