Cue the “Bossa Nova Style” rhythms and get ready for warbly, lo-fi melodies, because you can make your iPad or iPhone party like it’s 1971 – free this week only.

The Optigan is deliciously dated. The contraption used optical discs and photodiodes packed in “Temperite” molded plastic and covered in switches and buttons. (The optical approach puts it on a timeline with early Soviet synthesis, among other things – see Derek Holzer’s history of tonewheels, or for another app recreation of the technique, the gorgeous ANS, as seen on CDM.)

The sound is less Tarkovsky score, and more like what you’d expect of an organ advertised in the Sears catalog and promoted by The Donna Reed Show star Carl Betz. And iOptigan can reproduce all of that kitschy oddness, as in this fantastic demo tune. (I love the creators for the period jetliner footage. Book me a ticket on 1971 United, please.)

iOptigan adds a recreation of the optional spring reverb, metronome, MIDI I/O, MIDI chord detection, Inter-App Audio, file sharing, a sequencer with MIDI file import, built-in help throughout, and tons of thoughtful, historical details.

Here’s the chord detection and how to use it:

You should spend money on this. You would spend money on this. But take this free opportunity to really set a different mood and transport back to the 70s.

The app itself has a nice lineage, too. Stefan Stenzel of Waldorf teamed up with Pea Hicks of to make it. And in addition to grabbing the app, you can give yourself some nice linkhole time on that site to explore the instrument’s history and future, complete with obsessive details of all the variants and an exhaustive catalog of optical discs.

And if the kitsch factor didn’t win you over, a small group of makers has taken the wild set of creating a new Optigan instrument – the Panoptigon, which sounds as sophisticated as its Jeremy Bentham reference would lead you to believe. It’ll set you back a cool $3999, but to be honest, wouldn’t it be better in a way to splurge on this rather than a conventional keyboard or modular? Well, if I had such money, that is.

The results of that invention are poignant, not kooky – fuzzy, irregular piano loops are simply transcendent on their demo video.

Take a listen, as I was entranced – it’s almost a shame that this says “disc demo” on it or has a picture of gear:

Here’s the new instrument in action:

And maybe that’s the lesson of this whole phenomenon – the beauty of technologies that others might simply have forgotten or literally tossed in a bin. It sounds, eerily, almost futuristic.

Something to think about as I noodle around on the iOptigan recreation tonight. As with the other stuff mentioned today, don’t be shy if you make something and want to share.

iOptigan for iPhone, iPad at the App Store

Bonus freebie – the great piano samples you hear in the disc demo are open source.

Photo credit / CC-BY-SA 3.0 (nice Wikipedia article, actually!):

Main and chord keyboards of a model 35002 Optigan Music Maker optical organ, ca. 1971. Owned and photographed by user PMDrive1061.