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Survey of Turntable-like HCI for ScrubbedMedia Performancepaper (do not distribute)

Synopsis:- Survey of turntable-like human computer interface- Descriptions of several projects and products- Proposal for future work on disky- In search of haptic feedback

Motivation:- I have my own turntable-like interface project that I want to put in context and

understand- Want to see what has been done, so I can do something different and better- This is the oldest, newest instrument, so it’s important to watch what happens

with it- Explore NIME proceedings

Fundamental Characteristics:- Tight mapping between rotational position and sound phase- Normally motor operated between 0 and 100 rpm, variable- Graceful operation under manually interruption (scratching)- 12 inches in diameter (nice human scale)- 1.8 seconds of sound per revolution (approximately)- Smooth transition between very fine and very course control- Optionally discontinuous (moving the needle)- More??

Survey of turntable-like human computer interface (in search of haptic feedback):- Use traditional turntables (digitization)- Use traditional turntables (augmentation)- Experimental interface (turntable metaphor)

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Final Scratch:- Uses traditional turntables without modification- Special time-coded records to represent rotational phase- Hardware system, originally for BeOS in 1998- Lots of third-party software- Hardware costs $300-400- RZA invents digital turntable? http://www.youtube.com/watch?v=TXsYXMqw4Zchttp://en.wikipedia.org/wiki/Final_Scratch

Final Scratch Time-code:- 1200 Hz, amplitude modulated sine wave at reference speed- Left and right channels offset by 90 to allow direction detection- Speed determined by comparing tone to 1200 Hz reference- Position encoded in 40 bit time code (error prone)

Hardware System:- Scratch Amp decodes analog time-code signal into position, direction and speed- Computer receives this information and produces digital audio stream- Scratch Amp decodes and amplifies audio streamhttp://www.youtube.com/watch?v=Smt9B99iJ5I

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Tascam TT-M1:- Attaches to a traditional turn table- Determines position, direction and speed- Closed system, only works with some cd dj products, but has been reverse

engineered by Audile- Costs about $100- Why not use an optical mouse sensor?http://www.datasheetcatalog.org/datasheet2/9/0opeydz8pk55dp30dczkyk0ttzpy.pdf

HDDJ of ColorDex Dj System:- Part of the ColorDex Dj system in NIME 2007 - Do it yourself project- Decodes motor signals with comparator circuit- Not scratch-able: “While suitable for our requirements, the HDD solution does havesome limitations: chiefly, it requires some amount of spin, above acertain threshold, for the motor to output measurable signals. As aresult it is not possible to detect small ‘scratch’-like movements,and as such is not a replacement for a digital turntable. It is stillwell suited as a rotary input device that spins effortlessly and hasa high tactility factor...”- But what about this? http://www.youtube.com/watch?v=ecsrhdqIdZw&feature=relatedhttp://www.youtube.com/watch?v=Q8zkL36f9oI&feature=relatedhttp://www.instructables.com/id/HDDJ_Turning_an_old_hard_disk_drive_into_a_rotary

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D’Groove:- Uses expensive, very high resolution encoder/motor- 14,400 counts per revolution rotary encoder ($$$)- Too expensive to be a DIY project- Implements awesome haptic feedback stuff- ICAD 2003- Mentioned in Alex Norman’s thesishttp://www.youtube.com/watch?v=OHIl4F2JcEAhttp://www.cs.ubc.ca/labs/spin/projects/dgroove/

D’Groove:

- “We can produce bump like feelings on the turntable by sending it varying amountsof current with respect to its position. We can control the height and number of bumpsaround the turntable as the user moves the platter. Each bump can correspond to a beatin the song, enabling the user to feel the beat structure as the platter is moved.”

- “By altering the damping forces, we can vary the resistance felt by the user asthe platter is rotated manually. The amplitude of the song is mapped to the frictionapplied to the turntable so that heavily damped “muddy” spots can correspond tomusically “heavy” (or frequency rich) moments in a song. Lighter musical moments(breaks) can be accompanied with less damping on the turntable motor. Thus the user canfeel musical events in the song when in this mode.”

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You’ve seen this…

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Where to go next with disky:- Design is still relevant, make instructable- Use new teensy platform for full usb: http://www.pjrc.com/teensy/- Revisit original optical mouse part idea in like of new, faster parts- Study D’Groove!- Implement motor control- Do what D’Groove does, better- Bring real research ideas to DIY communities- Do Greg’s pressure feet idea- Workshop next fall, please consider it