- I have made a couple of PVC air horns.
- They can be made in several sizes, from 1/2" ID to 2" and possibly larger if necessary.
- They can (theoretically) be tuned.
- I have a few MIDI files for Bach organ fugues that I had arranged for brass quintet.
- I have a way of controlling the air horns electronically.
Therefore:I am building an air horn organ.
Progress so far:
- MIDI files can be processed using python in order to track what notes should be sounding at a given time (data point at each note-on or -off event)
- processing made possible by python-midi
- control of a single shift register (mostly) functional
- I'm using SN74HC595N latching shift registers from Adafruit for signal-level output
- control is based on py-spidev
- power control tested, theoretically functional
- ULN2803APG 8-channel driver for power output, supposedly can take 500 mA per pin
- miswired something and fried one of the shift registers and the RPi2 that I was using to test
- determined that there are no HDMI cables in the house to hook up the RPiA+ to the TV
- determined that my WiFi adapter won't work with Raspbian (OS on the Pi)
- learned to solder
- designed and ordered first iteration of the controller PCB from oshpark.
Things to do:
- program control script for the actual output
- test out control boards
- find viable inexpensive valve solution
- revise control boards
- build lots of air horns
- tune lots of air horns
- tune even more air horns
- check complete control system
- devise interface
- final construction
Explanations of the details will follow as I have the opportunity. I'll discuss how the control system works, how the air horns are made, and I'll talk about stuff that goes wrong (or right) as I go along. I'll try to update at least once a week.