Building a Better Rotary Potentiometer knob for the Digital Age - Page 1
Forum section: electronics / general

author: jonovid
author_rank: Super Contributor
timestamp: February 23, 2021, 04:15:44 pm
content: another hypothetical designmost of us know about the digital potentiometer and its rotary encoder so it has the same or similar functionality to an analog mechanical potentiometerhowever the digital potentiometer, has full digital control over its knob setting even remotely. regardless of the mechanical knob setting.however here is an idea I have had for some yrs now. what if a rotary encoder knob could show digital position markings!in some way display the digital value of the digital potentiometer setting on the mechanical rotary encoder knob its self.using individual LED ring design or a 2 digit 7 segment mini LED display inside the face of the mechanical knobinside a custom concentric knob.shaft dimensions or shaft type maybe a concentric design.a word about mechanical knob actuators,this post is Not about using DC motors to move mechanical potentiometers by friction clutch.so a potentiometer knob can be moved without forcing a mechanical actuator.the hypothetical design idea here is about rotary encoder body and rotary knob design.electronic component design. in the hope that a manufacturer will take up the design shown here.or improvements in a new better design. any suggestions? or knob design Blender art orknow of a rotary knob manufacturer already making acomponent design like this?. if so, just kindly disregard this posting. and please add a link to it.here is my hypothetical designits a panel mount coaxial knob of a custom concentric design.that is both a display and rotary knob in one unit.the parts of a hypothetical rotary encoder & concentric display knob design.only needs one 3/8" mounting hole 6.75mm diameter. Includes nuts and dress washers.the display bezel design. has the individual LED ring in the bezel outside the shaft bushing behind the knob.using the same panel mount .here are two working examples of the rotary encoder showing a digital position design.both are rudimentary in concentric knob design. however show some circuit design functionality we are seeking here.just in a more compact form factor then thay have made, so the electronics can fit inside the knob.this is something only by skilled manufacturers with custom made flexible pcb materialA rotary encoder with LED displayhttps://www.waitingforfriday.com/?p=381The project is based around a 24 position rotary encoder, 16 LEDs arranged in a circle around the encoder,an A6276 16 LED serial driver IC and the PIC182550 microcontroller.Posted by Simon Inns on May 9, 2010video linkhttps://open.lbry.com/@WaitingForFriday:a/Rotary-Encoder-with-Feedback-Display:fhttp://www.waitingforfriday.com/index.php/Rotary_Encoder_Demonstrationhttps://oe.com/rotary-b-clickwww.mikror this name rotary-b-clickwww or rotary-b-click if link not working just look for this thing calledrotary-b-click

author: ajb
author_rank: Super Contributor
timestamp: February 23, 2021, 05:15:41 pm
content: This is something the music control surface market has been dealing with for a while, but mostly where some sort of level indication is desired they just do a ring of LEDs around the knob. I suspect that the net result is the same amount of panel space versus a knob that is large enough to have a display integrated into it, but the smaller knobs with external indicators give you more finger space between adjacent knobs which is an advantage in a lot of midi controller and similar applications where the density of controls matters. See the Midi Fighter Twist for one example.Having a display inside the knob would be slick, but I can't imagine it becoming an off-the-shelf part at any reasonable price. Looks very much like a job for injection molding and maybe a rigid flex PCB which isn't going to be cheap to get into production. Going to a larger knob size with a real ring-shaped encoder would make the whole thing easier, and more likely to justify a price where the investment makes sense. Maybe even integrate one of those round smartwatch displays in the middle like the Nest thermostats do.For another interesting solution, there are audio mixing desks that put a line of encoders on a very thin rail mounted over a large LCD and use the display area around the knob for parameter information. If you've got a lot of knobs it's a relatively cheap way to effectively get a ~240x120 full color display for each of them. Here's an example:https://www.soundcraft.com/en/products/vi1000. Doing something like that on a little ~6" TFT would be a fun little mechanical design project actually.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 23, 2021, 05:46:03 pm
content: Not sure I got what you really wanted to do or at least what was new about it. As you showed, there's a Mikroe board which does just that, but Sparkfun also used to have a similar board more than 10 years ago (it's now retired for some reason, lack of interest?):https://www.sparkfun.com/products/retired/10407I'm sure you can find tens of such boards around.Do you mean to do something like this but directly integrated inside a rotary's encoder shell? How would that look exactly? How could we see the LEDs when a knob is installed?And now if your idea is just like the above, again what's new about it?

author: PlainName
author_rank: Super Contributor
timestamp: February 25, 2021, 11:51:06 pm
content: Something that might work for you was available a while ago:https://www.eevblog.com/forum/crowd-funded-projects/i2c-encoder-v2/Looks like the embedded LED version is still available:https://www.tindie.com/products/saimon/illuminated-rgb-encoder/Essentially, this is a rotary encode with RGB LED inside and a clear knob. For your purposes, you might have one extreme set to blue and the other red, then the colour in the ranger red...yellow...blue would denote the setting of the encoder.

author: tooki
author_rank: Super Contributor
timestamp: February 26, 2021, 05:19:57 am
content: You know they make larger-diameter, hollow shaft encoders for this type of design, right? Google “alps ring encoder”.

author: jonovid
author_rank: Super Contributor
timestamp: February 26, 2021, 12:47:08 pm
content: I will give it another try for a more compact displayanother hypothetical design idea is to used the sparkfun rotary encoder LED ring breakout board or othersbut add a two part coaxial light pipe collar to a larger size mounting hole. see imagea two part coaxial U-shaped portion of light pipe set in between two spline sides of a 13mm diameter coaxial collar andso that all 16 or 20 LEDs are represented on the other side of the pipe collar inside the light diffuser bezel ring the knob indicatorlight pipes can bend light around corners and tight spaces delivering excellent visual indication with minimal loss of light intensity.made of optical acrylic or polycarbonatelight pipe is set in between two inner and outer black plastic spline sides of a two part coaxial collar'so the light pipe has a gap between the front and rear of the coaxial collar.the 20 light pipe fingers are inclosed between two inner and outer black plastic spline sides of a two part collar.with this rotary encoder LED ring is set inside the case faceing the 13mm diameter mounting hole onto the back of the light pipe collarwith all 16 LED in alinement so the rotary encoder axle will go into 6.75mm diameter inside of the 20 light pipe collar.Quote from: tooki on February 26, 2021, 05:19:57 amok I did look at this oneQuote from: SiliconWizard on February 23, 2021, 05:46:03 pmI did the light pipe collar image artwork based around the sparkfun 16 LED ring using Paint Shop Pro 2002 version of Jasc Softwareplastics parts manufacturers are free to copy or use my collar image artwork if its of any help.Thank you all I will check all the links for design ideas, Thank you