Unique Clock Finally Unites Hackers And Sequins

We’ve all seen the two-color sequin fabrics you can “draw” on by dragging your finger over so the pieces flip to the other color. It’s fun stuff to play with, and very popular with the kids right now, but if you asked us if the material had any practical application we’d have said no. But that was before we saw this clever clock created by [Ekaggrat Singh Kalsi] that he calls Sequino.

Since a clock (at least one that only shows hours and minutes) doesn’t need to refresh very quickly, [Ekaggrat] thought that the sequin material could work as a display. Of course the tricky part is figuring out how to actually draw on it reliably. It can’t be done from the back, and since the sequins are plastic, you can’t use a magnet. The only way to do it is with a robotic “finger” and some very slick kinematics.

The most obvious feature of the Sequino is the belt drive that goes the length of its cylindrical shape. When the two motors connected to the belt are turning in the same direction, the pointer is moved left or right. But when the motors turn in opposite directions, the tension on the belt forces the pointer to extend and contact the sequins. It’s like an H-bot , but with the shortest ever Y axis. The front bar is moved up and down with rotating rings inside of the device. It will probably make a lot more sense once you watch the video of it in operation after the break.

[Ekaggrat] says this project was developed as part of his quest to build “doodle clocks” that draw out the time continuously. The advantage of using the sequin fabric is that it shouldn’t be damaged by repetitive use, an issue he’s tried to solve via photonic means in the past.

24 thoughts on “Unique Clock Finally Unites Hackers And Sequins

  1. Interesting and very well done.

    But isn’t it a bit energy consuming and noisy as a clock? not for bed side usage, of course :-)

    I can imagine other cool purposes for stuff that don’t need to be updated frequently. Like a painting that changes day or night

    1. Well anything that was made would have to be in just one colour, and fairly low resolution, but maybe a calendar with a different quote each day? (On a larger surface of course.)

  2. “The advantage of using the sequin fabric is that it shouldn’t be damaged by repetitive use”

    Since it’s a bistable material, there has to be some deformation or tension happening somewhere. This won’t last forever either. At some point the sequins will just start falling off.

    1. Really does depend on just how much stress is applied. A spring that isn’t ever pushed near its limits can last basically forever where work it hard and it will die very fast. In this case I don’t expect it to last very long, but the idea could work really well if you can make the bistable part low deformation – which might make it a little less stable but for something that is updated frequently by design letting gravity with just a little assitance take over a pixel hardly matters.

  3. Also “It’s like an H-bot , but with the shortest ever Y axis.” Isn’t it more like the worlds most multifunctional belt tensioner? It looks to me like it’s the belt tension that pulls the tip against the material and the tension on the belt is maintained by a spring inside. An H-bot uses 2 separate belts, this looks like it is one belt continuously from one motor pulley to the other. Certainly a clever idea!

    1. I’ll go either way on whether or not this is an H-bot. And I’m to blame for wedging that sentence into Tom’s otherwise flawless piece. :)

      The OP, Ekaggrat, described it as an H-bot, and I can see what he’s getting at: when the two motors turn in the same direction, the shuttle travels, and when they oppose, it travels perpendicular to the belts.

      And H-bots only have a single loop. And I don’t think there is a spring. Look carefully at the design and you’ll see that the belt runs on both sides of that exterior arm, pulling the “finger” in and out just like with an H-bot. I think belt tension is constant.

      But there’s an extra pair of fixed idlers in the canonical H-bot, and I can’t really see how they map into this one, so maybe you’re right too?

      Anyway, it’s certainly the coolest mechanism I’ve seen in a while. Maybe excluding Ekaggarat’s other crazy clock: https://hackaday.io/project/29509-edgytokei.

      1. Huh, I completely missed the inside part of the belt somehow. Guess I cam up with another (theoretical way) one could build this.

        Still don’t think it’s quite like an H-bot. One could say its “almost, but not quite, entirely unlike an H-bot”

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