Velokeys

Velokeys is a project to make a velocity-sensitive qwerty keyboard.

Pictures!

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  Initial concept sketches

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  Initial concept sketches

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  This is everything found inside the GearHead keyboard I'm using. I removed all the rubber domes from the switches and placed them in a baggy. I don't expect to use them.

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  Here's a beauty shot of the keyboard PCB.

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  And here's a close-up of the belly of the keyboard bed.

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  I digitized the layout of the sensor matrix and its screw holes just in case I need to create a spacer between the two sensor matrices. This is a picture of the layout cut out of paper and out of chipboard using a laser cutter.

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  Here's the sensor matrix sandwiched between a rubber band and the PCB so I can test keypresses.

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  Testing springs of different lengths. Here's a video: http://youtu.be/_dQA3hZ6M80

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  I placed one sensor matrix on top of another to verify that the sensing technique will work. Here's a video: http://youtu.be/Y9ymcLa4O9I

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  Here's a quick sheet outlining the kinds of sounds this thing will make. I'm not sure if incomplete keypresses will be an issue, but in the case that they are, the BONK noise should be a a nice workaround.

Similar work

• https://ccrma.stanford.edu/wiki/Laptop-Based_Step_Sequencer
• https://ccrma.stanford.edu/wiki/Daniel_Smith_Final_Project_Music_220a_Fall_2008
• http://wiki.lvl1.org/Isomorphic_Keyboard
• http://benzguo.com/bayan/
• http://www.c-thru-music.com/cgi/?page=prod_axis-49
• http://www.davecooper.org/blog/2014/10/15/i-built-a-keyboard/
• http://deskthority.net/workshop-f7/brownfox-step-by-step-t6050.html

Minimum viable product

Requirements for MVP

1. Velocity sensitive keys on at least whole alphabet and # key's
2. Working MIDI mapping driver (OR MIDI over USB from Arduino)

Nice-to-haves

• Custom enclosure
• More expressivity controls
• Lighting

Given unlimited time... (and therefore money)

• Pressure sensitivity
• Lighting on each key
• NKRO (no keyboard ghosting, each key can be pressed individually)

Materials

The materials used can really vary based on the things I can get my hands on, but the two things that remain fairly constant are the switches used. I'm basing the velocity sensitivity off of this diagram from the isomorphic keyboard project listed above.

• Mechanical keyboard switches (from http://www.gonskeyboardworks.com/switches/46-cherry-mx-switches-63-2-pcs.html)
• Tactile switches (from http://www.digikey.com/product-search/en/switches/tactile-switches/1114206)

If I can find an adequate midi controller from a velocity-sensitive midi keyboard, I would love to use that for the "brains." Otherwise, I will need to use an Arduino with a couple multiplexers to open up enough inputs for all 41+ keys (with two switches per key). That will be pretty daunting.

If I can find an inexpensive mechanical keyboard, then I can save quite a bit of money on switches and an enclosure and all the other materials. I plan on heading to the electronics surplus store soon to try to dig up a keyboard or two.

Plans

1. Gather materials
2. Prototype with available materials
3. Build CAD schematics
4. Build structural components
5. Solder electronics
6. Write software driver
7. Success