Using an air compressor and branching network of air tubes and valves, the Siren Organ works by blowing air into a series of spinning discs. These discs have laser-cut concentric circles of evenly-spaced holes to produce harmonically related pitches, and spin using a variable resistance motor powered by Arduino. We built 3 unique Siren Organs, two using different types of valves, and one designed in SolidWorks and made with a lathe, amongst other machining tools at Stanford's Product Realization Lab (PRL). Made with Dan Somen and Kevin McElroy. Submitted to NIME 2014 and presented at Maker Faire in San Mateo the same year.