Many things that humans do are very difficult for machines. Case in point: tying shoelaces. Think of the intricate dance of fingers crossing over fingers that it takes to pass off a lace from one hand to the other. So when a team of five students from UC Davis got together and built a machine that got the job done with two hooks, some very clever gears, and two motors, we have to say that we’re impressed. Watch it in action on Youtube (also embedded below).
The two-motor constraint would seem at first to be a show-stopper, but now that we’ve watched the video about a hundred times, we’re pretty convinced that a sufficiently clever mechanical engineer could do virtually anything with two motors and enough gears. You see, the secret is that one motor is dedicated to moving a drive gear back and forth to multiple destinations, and the other motor provides the power.
This being Hackaday, I’m sure that some of you are saying “I could do that with one motor!” Consider that a challenge.
Meanwhile, if you need to see more gear-porn, check out this hummingbird automaton. Or for the miracles of cam-driven machines, check out [Fran Blanche]’s work with the Maillardet Automaton.
Thanks [Itay] for the tip, via Gizmodo.
Sweet jesus. That’s amazing.
Pure elegance
At first while watching I was like: “Ha, it can’t even tighten the first simple knot, this machine will not do a good job!”, 5 secons later, i’m here, speechless, with many questions that need answering.
This. So much this.
This is how we become the Jetsons. Now wheres my sky condo.
We need the nuclear war to render the surface world uninhabitable first…
We are working on that.
It’s not uninhabitable – the surface just where the Flintstones live.
Jetsons or Zardoz?
One motor to select function sequence and the other to perform it, this allows you to make any mechanism doesn’t it? Sort of like a Turing complete robot?
So show me your delta 3d printer design please. :)
Why, explain in principle why it can’t be emulated with enough small enough steps?
Theoretically, you could even use just one motor if one rotation direction selects the function sequence and the other direction executes it. In practice this would be ridiculously complex mechanism of course.
One printer I had used this principle. Turning in one direction turned various cams. Turning in the other direction would cause an action depending upon which cam mechanism was engaged.
using a ratchet and cams instead of a second motor, clever.
some of the newer lego technic sets have multi function gear boxes for this kind of thing. like a single motor controlling several functions. this just puts a second motor in control of the mode switching.
They’ve been around a bit longer than that. Unless I’m younger than I feel. 1993 was quite some time ago.
https://brickset.com/sets/8082-1/Multi-Model-Control-Set
I have been sitting here watching this in slo mo, which is a real change as I normally watch tech stuff at 2X and I am still in awe of how the line between simplicity and complexity blurs. Very cool machine.
this is fun! Very interesting to see the gear shifting, You would say it would be easier cheaper better to do this with more motors. But this if perhaps far more interesting to watch, nice job! Thanks for posting.
Also looked at the automaton video as mentioned in this post. That was perhaps even more amazing. What I mostly wonder is how they made the cams to operate the automaton, in order to make such a wonderful picture. I must have took a very very long time to create the cams for all axis. I know it is essentially clockwork technology with a extra levers operated by carefully shaped cams. But see it operate is like magic. For one reason I want to learn all there is about it (how they made it what challenges they experienced with the tools of that time) and on the other side I want to preserve the magic (by staying away from all possible info). But anyway, it wouldn’t hurt if hackaday did a special item about automatons.
Okay, not bad.
“I’m sure that some of you are saying “I could do that with one motor!” ”
in the ‘olden days’, most automated machines operated with just one motor or drive. Whole factories ran from a single water wheel, using cams, timing belts, etc.
I can do it with NO motor!
My kids, on the other hand, use Velcr0, and see no point in learning such arcane crafts.
You don’t need to go that far back. the allis chalmers round baler used a fully automatic baling, twine knotting and cutting system without hydraulics or electrics. It was probably the peak of mechanical ingenuity for round balers to this day.
That kind of mechanism has been done for years in Lego, because the programmable bricks have a limited number of motor ports (and, even if you had more ports, additional motors are more expensive than the parts to build a mechanical multiplexer). And yes, there are single-motor versions. The limitation of those is that they can only advance through the outputs in one order, and they usually can only turn the outputs in one direction.
https://www.youtube.com/results?search_query=lego+multiplexer
A sewing machine has only one motor and does the same kind of knot
Not the same kind of knot. In fact, not a knot at all, unless you’ve got a very weird sewing machine.
Mine does many amazing stitches it’s one motor and cams, but knotting is left to the human.
The important bit here is the simplification of the actual knot tying. Instead of finger twiddling, reduce it to making two loops and pass one through another. I tie my shoelaces like that too, it tends to confuse people a bit.
Me too. I first learned that that method existed from a Sprint “Sprintcuts” ad (where they showed quick ways to do everyday things to highlight how fast their network is), but the ad didn’t show enough detail for me to figure it out, so I found a pretty good video on YouTube that showed how to do it. Unfortunately, I’ve never been able to refind that video to thank the person. It was a video of low production quality (just somebody who doesn’t normally make videos, using whatever camera they had).
I’m pretty sure I saw it in a RI lecture by Matt Parker.
I tried tying my shoes like that for a while. I’m just too good at it the old way.
What it did teach me, though: the shoelace knot is basically a square knot, but with the second overhand bit done with doubled-up string that makes it easy to undo. Whoah.
If you do a second pass through with the loops before you pull it tight, it will hold much better and still untie when you pull the ends. Try it!
As pointed out in the comments, it ties a granny bow. Both passes are the same, The pass with the loops needs to be the opposite of the first pass for the knot to hold.