Nice project, I can feel it as being very addictive …
Do you have an idea where to find these kind of digital knobs ?
https://vimeo.com/134030054
Love it. What a great idea. And the execution is excellent.
Seeing that one of these displays costs $25K, I’m guessing the knobs were custom built!
To me it sort of looks like 3D printer layer lines on the sides of the knobs. They might have 3d printed one knob and had a bunch cast from that part. (If that was the case you’d think they would have sanded it a bit more before casting.) Or maybe they’re all 3d printed.
Can anyone tell if the knob spins like a rotary encoder, or is it like a potentiometer with a limited turn?
My guess would be encoder. The reason I think that is because otherwise each one would need a motor to reset them back to their 0-position whenever the display gets blanked. And that’s a lot of motors, a lot of additional cost.
What I’d like to know is the material used that they’re shining light through. it appears black till the light comes on.
Thin black paper? Or black acrylic maybe?
I think you could use these rotary encoders with an RGB LED built-in, but you’d need to add a WS2801 (or similar) chip to make them addressable, right? https://www.sparkfun.com/products/10982
Maybe a thin coating of aerosol plastidip over a opaque plastic?
The matte finish suggests that to me…
@Ben_Delarre , maybe. I just think of how it would affect the light coming through.
@Jason_Coon , that will give you a single ‘dot’, as opposed to the full surface of those knobs.
@Jarrod_Wagner , could be. I’m thinking the plastic is also the diffuser for the LED(s) behind it. Hmm, worth some testing, and 3D drawings of what may be possible. Need to find a high precision encoder too.
Ah if only I had the time!
if you look closely then you see that they are STL / 3D printed parts.
A similar principle with optical detectors is shown here:
Other method is to use an encoder disk and a Transmissive Optical Sensor (those are dirt cheap)
http://frontrangerobotics.org/Jan05/EncoderForRML.jpg
http://www.pollin.de/shop/downloads/D121095D.PDF
The diffusor seems to be a tinted acryl glass
http://www.plattenzuschnitt24.de/Acrylglas-Zuschnitt/Acrylglas-getoent/Acrylglas--getoent-Schwarz-3mm.html?refID=2&gclid=CPamhdGRs8cCFRK3GwodafUB0g
… and under the knobs I would mount APA102…
How could you take input from that many rotary encoders? Do they make them addressable?
No, but that’s what MUX/DEMUXers are for. You can read a few of them on a single uC, but a bunch more with MUX/DEMUXing them.
Could be this normally black matte but translucent when backlit acrylic: http://www.acrylite-shop.com/US/us/color-changing-back-lit-i0f2hrgazr8/acrylite-led-p95-black-white-9h04-sc-juy7atttk90~p.html