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Prototype with infinite pivot lenght

burkey

Drew-r in Australia Lego is seen as evil satanic spawn because:

  1. It is overpriced plastic junk
  2. At 3am in the morning it can inflict serious foot injuries or worse! (Home Alone style!)

If someone buys your kid Lego as present without prior authorization then that's basically a declaration of war ๐Ÿ˜€

Perhaps similar sentiments exist in Portugal.



CyberGene

As a kid from a poor country we didnโ€™t have LEGO here and only a very few kids with rich parents (and maybe part of the socialist apparatus) had ones and I used to salivate a lot over LEGO. I was still a kid when the communism fell and they started importing them but my family was poor and LEGO was too expensive. Well, imagine my delight when my wife bought me a present a few years ago, my very first LEGO ๐Ÿ˜€ I mean, I couldโ€™ve bought myself a LEGO for a long time but I was already a grown man. The idea that someone got it finally for me as a present was a psychological trauma finally fixed after so many years ๐Ÿ˜ƒ


vagfilm

burkey Perhaps similar sentiments exist in Portugal.

We are simple people... It's just another way of saying "if you cannot understand how it works, I will dumb it down to you with lego and maybe it gets evident"...


QuasiUnaFantasia

Here in Denmark, where LEGO is from, no associations exist between that word and something bad. The man who invented it named it from the first two letters from each of the words in the sentence "Leg godt!", which means "Play well!"


vagfilm

Don't ger me wrong: lego is well loved here and it is probably the best seller toy during Christmas (coincidently, I just bought a huge set for my daughter yesterday because she was running out of bricks for her house projects...). What I mentioned is in the contex of a conversation between adults ๐Ÿ˜Š


QuasiUnaFantasia

vagfilm We have a similar expression in Denmark: "Must you have it cut out in card board?" This essentially means: "are you so dim-witted that you cannot understand it when it is explained normally?". Sometimes the phrase is used less aggressively: "To cut it out in card board โ€ฆ", meaning "To put it plain and simply โ€ฆ"


vagfilm

And the "make a drawing to you" in english (and also here). It's the same thing everywhere...


RIP

๐Ÿ˜… ๐Ÿ˜Š (the icon does not look embarrassed at all to me, like the one in PW)

Well, at least with my slipping of words, we all (and especially I) learned something.

I am still thinking of that possible mechanical adjustment which I mentioned in my last post:

RIP Then, by moving the seesaw back and forth (from pianist's view: left and right in the video) one could make this thing change the real touchweight of the keybed, not just the simulated one via the response of the audio! Wow! Isn't that amazing?

I think this is really amazing, and only because of this I might actually build an octave to see if/how it works in practice, even if it is useless to me. For sure after my Cybrid is complete though, so it'd be a while.

Perhaps we should ask @KawaiJames to come here and see if Kawai is interested in this? With all the smart mechanical engineers who must be behind their digital actions, I can't believe nobody has thought of this before.


vagfilm

RIP Then, by moving the seesaw back and forth (from pianist's view: left and right in the video) one could make this thing change the real touchweight of the keybed, not just the simulated one via the response of the audio! Wow! Isn't that amazing?

Not so fast, I think... You change the touchweight, but you also change the leverage of the key (ie, how much of key vertical down-displacement translates into vertical up-displacement of the action). So, you can only monitor the actual key movement to create MIDI events, since the action movements will change with each adjustment, and the calibration would be all over the place.
You can already do this in an acoustic grand action: if you change the screw-head type of capstan by a longer metallic piece, you can move the keys back and forth to different positions: that will also change leverage and alter touchweight. But now your hammers would be either flying off because of too much momentum, or would be still because the angular displacement of the whippen is not enough to make them move.
Boy, am I a sceptic or what???


RIP

vagfilm Boy, am I a sceptic or what???

Being skeptic is great in general, and typical of scientists like you are. Otherwise one would just waste all their time in conspiracy theories and creative nice-sounding pseudoscience.

And in this case, you are correct (but there is a twist). In fact this "touchweight regulation" won't work on a real acoustic action or even on a hybrid with hammer sensors (unless one adjusts only the sensors which is too much work).

However in this case there is no reason that the seesaw below the key moves a specific amount: any amount is fine. As in most digital pianos, the sensors can be in the key and the "action" is there only for giving some "right" feel. AFAIK, all the digital pianos with "fake hammers" have key sensors, not hammer sensors, and this one will be no different.


vagfilm

RIP Being skeptic is great in general, and typical of scientists like you are. Otherwise one would just waste all their time in conspiracy theories and creative nice-sounding pseudoscience

Not only that... You only have time to do a small number of experiments, so you need to choose wisely and be sceptic of your own experiments during your planning, otherwise you work a lot and end up with nothing to show... I believe that the most important thing I teach my grad students is to question their every move, and be the first critics of their experiments and data; then, once they are convinced that there is nothing wrong in their work, they should never let anyone question their results without the others doing the same amount of data probing that they have done already. Be sceptic, and then be proud...



Drew-r

spanishbuddha

Will it offend anyone if i were to say it looks like it qualifies as a hybrid?


RIP

Going back to this sort of stuff, here's a guy who also was serious about having a "too short of a pivot" while still wanting the action have a smaller footprint

https://youtu.be/S_vWSY5fdwQ?t=50

As you can see he also uses the parallelogram idea, however he makes the "double pivot" to move, which forces him to use a spring, which we don't like ๐Ÿคฃ
I am still wondering why nobody designed, patented and sold something like this: it does not look any more complicated than existing folded actions, while at the same solving the major problem some of them have with playing towards the back of the key (Privia?) or with excessive size/weight (VPC1?)


ambrozy

RIP
The finger will exert force at a certain point of the key and the inertia of the hammer will act with the opposite force not necessarily at the same point, it will force the flexure to bend in some wrong axis and I doubt very much that it will be possible to design such flexure that will be stiff enough (comparable to a wooden key) in all axes other than the one it is supposed to move, certainly not from any plastic.


Mind

I think the concept of "virtual pivots" in DP actions is pretty interesting. Both Kawai and Casio seem to have their own patented actions designs that uses a virtual pivot, which in theory, could allow a longer pivot action in a much more compact form.

Kawai's Patented Action: https://patentimages.storage.googleapis.com/f9/70/ee/a50b5a173b43eb/US12136403.pdf

Casio's: https://patentimages.storage.googleapis.com/b9/26/d3/1f2d1c75b76544/US12315474B2.pdf

I hope Kawai or Casio is on their way to releasing a model involving their own virtual pivot actions soon.


CyberGene

Mind these are interesting but I see some disadvantages with the Kawai one (and the Casio one I can't really understand it, maybe the back of the key slides through some guide...?):

The only fixed fulcrum is that of the hammer. And the one for the key is a floating one, linked to the hammer, so when the hammer raises, it pushes that floating fulcrum slightly upwards, thus creating a virtual pivot point. But that means that the key is permanently linked to the hammer which is known to be a bad thing for digital piano actions, you can't just tap the key to accelerate an independent hammer. Instead, both the key and the hammer need to move together.

Now, regarding the Casio one, as I said, I can't really understand how it works, I will have to dig into it more and I'm a bit tired today for this, but what I can see for sure is that the hammer is again linked permanently to the key, so it's the same critique I have.

Other than that, it's an interesting idea and I hope we can see some progress towards virtual (longer) pivots in compact actions. But more than anything, I'd love seeing any real escapement in digital piano actions. I guess by this point, it's already clear that we don't mean simulation of the escapement bump, but rather the complex detachment of the hammer from the key leverage which also changes the leverage ratio, and the backchecks catching and stopping the hammer rebound which removes the forceful pushback regular digital piano actions exert against your fingers.


_sem_

Mind

I've got the infinite-pivot CME xKey but it's not a hammer action, rather a set of space-bars.

I recall earlier versions that have never materialized. The Casio one looks too thick to be marketable.


Mind

CyberGene I'm kind of interested to know if there are DP action examples that shows how if

"the key is permanently linked to the hammer which is known to be a bad thing for digital piano actions"

as I think I may not be fully understanding your description?

What I currently understand about the Kawai virtual pivot design, is that compared to a "standard" design (e.g. their RH3), they added/attached a "second arm" connecting the standard hammer to the front of the key (the second arm itself is also connected to the main chasis I think), and the geometry of the second arm as well as where they connect all of them together dictates how much the fron the of the key dips relative to the back (which is sort of the same as pivot length).

The Casio's "cam follower" or the guide on the back probably traces out the trajectory of how the key will move as you depress it. So it's kind of like a "2d" key guide I guess?

In both designs, I don't think the key is fully rested on the hammer.

From the figures and diagrams in the Kawai one, it gave me a feeling that it's more "production-ready", and not just a concept level "in theory this might work" design.


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