Tag Archives: mark dixon

Safetybike


YIKES! Safetybike update 1/18/08: The Safetybike video will be featured this coming weekend on an CNN show called “News To Me” that runs on Saturday and Sunday at 12:30 and 5:30. Mark and Chris have put together a Safetybike website for inspiration.

Another one of Mark’s projects! To see more of his inventions check out the typewriter piano and the Invisible Chair.

Mark has also become the collective house’s resident hydrologist; you can see his directions for an inexpensive rain barrel here. That’s just a start–he recently found us two big plastic containers that will hold 275 gallons of rain water each, to be installed once we’ve finished replacing the gutters. Stay tuned…

1/10/08 SAFETYBIKE UPDATE: Crazy! The Safetybike video has caught on in a big way. In the last month it has gone from several thousand views to well over 1.1 million. If you Google “Safetybike”, page after page of links come up.

Mark himself is back from tour with Zegota and home sick with a bad cold. He’s not quite sure what 1.1 million views means to his own life, except that he and Chris Huggins are thinking about putting the actual Safetybike–resting against Mark’s parents’ garage for the last couple of years–up on eBay. We’ll see.

I’ve enjoyed looking at some of the responses to the Safetybike video. I think my favorite is this guy:

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20 Questions

My housemates Jodi and Mark are members of Invisible. Mark is co-creator of the Selectric Piano (and the dancer in this video); Jodi is at the keyboards. This description is from Invisible’s MySpace page:

“Here’s a Video of the song 20 Questions, performed earlier this year at 1001 in Greensboro. It features Jodi on the Selectric Piano, an instrument built by Fred Snider and Mark Dixon that interfaces a typewriter with a piano. notes and letters. The video was shot by Jon McLean and edited down by Bart Trotman.”

Tech info on the Selectric Piano:

“To begin with, the IBM Selectric typewriter is a marvel of engineering! The typewriter is 100 percent mechanical and employs a 6 digit binary coding system to direct its type ball to the proper latitude and longitude for each character that the typist types. To access that six digit code we placed tiny light sensing switches at each of six bars that transfer the keystroke to the type ball. The shift command adds another switch and thus a seventh digit to the code. That code is “cleaned up” electronically by circuits we mounted on the typewriter itself. The code is then sent via a printer cable to the piano playing assembly. There we use chips called ‘demultiplexers’ to translate the seven-digit binary code into a base-ten number between 1 and 88. Amazingly, the IBM Selectric types exactly 88 characters — that’s the number of notes a piano plays! That demultiplexed signal is amplified to 33 volts on its way to to contract the appropriate solenoid. Each key has its own dedicated solenoid and ‘finger’ assembly made from our plastic cutting board, some hard maple and brass rods for pivots. The piano-playing assembly sits in front of the piano on a bench. It is not permanently attached to the piano. Jodi applies sustain via a douglas fir two by four which is attached to the piano’s sustain peddle using two bent nails.

“Incidentally, some of the first ‘letter quality’ computer printers were IBM Selectrics that were rigged to computers in the exact opposite way as described above. Solenoids operated the typewriter’s six bars, shift and return functions. This was available as a package conversion but many old school hackers like Fred, one of the makers of the Selectric Piano, made their own at home.”

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