[HN Gopher] Faceless clock makes you think twice about how it works
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Faceless clock makes you think twice about how it works
 
Author : Tomte
Score  : 122 points
Date   : 2022-11-18 19:14 UTC (3 hours ago)
 
web link (hackaday.com)
w3m dump (hackaday.com)
 
| thunky wrote:
| This reminds me of the "hubless" motorcycle:
| 
| https://motorbikewriter.com/hubless-motorcycle-streets/
 
| SamBam wrote:
| Neat. I had figured the hour hand had a tiny gearing mechanism in
| the connection between the two hands. A magnet is a much simpler
| solution.
| 
| An old acquaintance of mine designed and sold an awesome
| wristwatch that used two ballbearings attached by magnets. [1]
| Not only was it useful for blind people (it was a much better
| mechanism than the old watches with an openable face, which could
| get misaligned by touching) but it was also fun to play with, as
| you could spin the ball bearings around and they could get caught
| again by the magnet. The video of the person spinning the hour
| hand reminded me of that.
| 
| 1. https://www.eone-time.com/
 
  | justusthane wrote:
  | > I had figured the hour hand had a tiny gearing mechanism in
  | the connection between the two hands.
  | 
  | They have a previous version that was exactly that:
  | https://www.youtube.com/watch?v=XCOC2zNjWCg&list=PLAYNJqEoXT...
  | 
  | The movement of the hour hand is pretty terrible though.
 
  | munk-a wrote:
  | Yea - I'd assumed the hour hand had some sort of dead-reckoning
  | compensating gear on the joint in the middle of the clock
  | similar to a south-pointing chariot[1]. I'm actually a bit
  | disappointed they used magnets since it'd be so easy to mess up
  | the orientation with a bit of otherwise benign interference.
  | 
  | 1. https://en.wikipedia.org/wiki/South-pointing_chariot
 
    | divbzero wrote:
    | > _I 'm actually a bit disappointed they used magnets since
    | it'd be so easy to mess up the orientation with a bit of
    | otherwise benign interference._
    | 
    | That happens to a fair description of magnetic compasses as
    | well. I suppose that's why some compasses use a modern
    | version of the south-pointing chariot (gyroscopes).
 
  | netsharc wrote:
  | I wonder if they used gears to move the hand clock, if it just
  | needs to be rotating at a constant speed... I think so, 330
  | degrees counter clockwise per hour? Since, as the minute hand
  | does a full rotation, the hour hand needs to travel 30
  | degrees..
 
    | munk-a wrote:
    | Sort of - you'd need to have some system for clock adjustment
    | to fix for DST, clock drift and the like that would also need
    | to be incorporated into the spin. So just a constant low
    | powered spin counterclockwise wouldn't be quite the full
    | solution.
 
| Alexmania wrote:
| Konstantin Chaykin built a watch similar to this called the
| Levitas, seems really awesome.
| https://chaykin.ru/en/watches/levitas/
 
| IshKebab wrote:
| I always wanted to make one of these with fully floating hands
| using invisible thread.
 
| plgonzalezrx8 wrote:
| Love the "no bullshit" articles that explain things quickly and
| clearly. A+ Work on this blog post.
 
| mortenjorck wrote:
| Projects in this space tend to be fairly niche, geeky proofs-of-
| concept with a Woz-like fun factor but little mass-market appeal.
| 
| This, however, has plenty of both. With a little polish to the
| industrial design and a high-quality contract manufacturer, I
| could absolutely see this becoming a popular item in homes and on
| desks.
 
  | ok_dad wrote:
  | No, not everything needs to be turned into a product for the
  | capitalistic machine. Let us have some fun without trying to
  | make a buck off of it!
 
  | [deleted]
 
| CobrastanJorji wrote:
| I'm sad that both hands aren't magnetic. It'd be much more cool
| if the whole hand assembly floated. I suppose the two sets of
| magnets might interfere with each other as they pass by. I wonder
| how far you'd need to separate them to make it work.
 
  | CrazyStat wrote:
  | Making stuff float with magnets is hard. You have to replace
  | the permanent magnets with electromagnets and then have a while
  | bunch of sensors and logic to drive the electromagnets. I can't
  | see a way to make it work in a clock like this.
 
    | CobrastanJorji wrote:
    | Ah, I see. What about those cheap "floating globe" or
    | "levitron" desk knick-knacks? Do those maybe only work
    | because they freely spin, whereas a clock could not?
 
      | CrazyStat wrote:
      | They work because they have a reasonably large base and a
      | reasonable stable thing floating. The clock hands aren't
      | stationary, let alone stable, and since clocks are
      | generally flat in one dimension you have pretty limited
      | space to play with.
      | 
      | The only way I've thought of to make it work would be to
      | have a fairly large "hub" at the center of the floating
      | thing, with the two hands coming out off the floating hub.
      | But that would be much less visually impressive, I think.
      | The hub would have to be large enough that the movement of
      | the hands is relatively miniscule in terms of weight
      | distribution.
 
    | munk-a wrote:
    | I think (especially considering the different needs for 6:28
    | PM and noon) that you'd need some orthogonal magnets set up -
    | have one set of strong magnets around the center of the hub
    | to keep it in place while providing a minimal amount of field
    | interference to the magnets driving the hands. I'm not an
    | engineer but I think any solution that starts with trying to
    | suspend a clock using magnetic forces applied to the clock
    | hands is going to be incredibly complex and hour-minute
    | cross-overs would be extremely delicate maneuvers considering
    | how much of a raw magnetic field you'd need to be projecting
    | just to keep the clock face floating in air.
 
| bee_rider wrote:
| Clever and elegant
 
| [deleted]
 
| [deleted]
 
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