The Sound of Sirens

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Drawings

Old sketch of "siren disks" mounted to a bike wheel.

Bike-siren2.jpeg

Older sketch of the sort of timbre that you can create from different holes in a disk. What looked like it would be amplitude modulation (and probably is, to an extent) is actually a rich harmonic series, according to Bart Hopkin.

Toneholes.jpeg

The siren organ with one motor and faders controlling the flow of air (pressure/volume).

1-motor.jpeg

The siren organ with faders controlling the speed of the motor--a hybrid design with the above.

Many-motors.jpeg

Examples of other work

(* what the hell NAMTA? http://www.namtamusic.com/siren-wi-organ-lessons)


MVP. We built a disc with evenly spaced holes attached to a rotating motor and a 9V battery. Blowing on the spinning disc does indeed produce pitch! The motor was rather noisy until we figured out a position to squeeze it (near the top) that makes it virtually silent. Then, we iterated, and attached a potentiometer (fader) to control the voltage. This successfully created a moving pitch that sounded very siren-like!


The Plan. We want to build a "siren organ" with some faders to control rotational speed of the motor(s) (frequency), other faders to control the applied air pressure (volume), and buttons to control solenoid valves to turn the sirens on/off.


Unlimited Resources Vision. It's more about unlimited money than time--I think we can achieve something cool. We're ditching the bike idea, I think.


Elevator Pitch. An "organ of sirens" with the feel of a MIDI instrument. Faders control the volume and frequency of mechanical sirens, while buttons turn them on and off.


Materials Needed
motors (5, one for each disk)
tubes/air hose (10)
solenoid valves (10):
* 7psi model (might need more): http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_169835_-1
* air directional control valves: http://www.mcmaster.com/#air-directional-control-valves/=p6xufn
arduino (1)
power source (1?)
keys/piano/organ interface (faders + buttons + enclosure)
disks (5)
enclosures for the disks (5)
horns? (5)


Next Steps. The next steps are to build a 5-fader, 4-button, 1-motor model, where 4 faders are devoted to air hoses over the individual rings of 1 disk (different pitches) and control the air pressure of each hose, and 1 fader is dedicated to the spin of the motor. The 4 faders could possibly control ball valves to partially open/close the air hoses as opposed to flow, which we do not have a good grasp of how to control (cheaply; a regulator might work). The buttons could also serve as the valve control, or could power on/off the air supply.

We need to figure out how fast we want the individual motors to go, and how much power they need to all spin at the same speed. This will let us tune our organ.