aeh5040

OK, I managed to make a bigger (2 octave) version of this: Previously I thought this would not be possible because it seemed to require a width of 5 studs per hammer, which would make it much too wide for the glockenspiel. However, I managed to find a way to reduce it to 4 studs by sneaking two differentials in next to each other. (With LEGO there's always a way!) The reduced width also required a different hammer actuation mechanism. The whole design has also ended up much more rational and robust.

That's really amazing! I also wonder whether the parameters could be tweaked to get it a bit smoother. Presumably there is a PID controller involved.

That's quite a stunning model, and very unusual!

We miss you Eric. Wonderful to see that you are still in the game!

So it seems the B model centre of gravity is shifting from official designs to community ones. I guess TLG has concluded that B models don't drive sales, and the effort of designing and quality-controlling them isn't worth it. A shift toward a general expectation of community B models could be a positive thing for everybody, if the general LEGO-buying public were aware of it and knew where to look. We just need to get the New York Times (or whatever) to publish an article about the phenomenon... Do the same observations hold in themes besides technic?

Very interesting!

I've been similarly frustrated with these for a long time. The earliest example I'm aware of is this one from 2001. http://www.last-outpost.com/~malakai/lego/

Thank you for the kind remarks, folks! OK, I guess I have to produce instructions (no kidneys necessary). In the meantime, it is very similar to the synchropods, for which I already made instructions https://rebrickable.com/mocs/MOC-8109/aeh5040/synchro-pods/. And maybe I'll post some pictures... That's right. The ratios are 72:73:74:75:76:77:78:79:80. Yep, pretty much a perfect explanation. No particularly strong reason for only using 8 hammers. I just thought an octave and an 8-beat rhythm might sound better musically. One very important detail is the use of the white clutch gears, which enable fine adjustment of the timing. I was concerned that they might slip over time, but there's no evidence of that at the moment. The hammers don't need much torque. I also made lot of use of the little technic rubber thingies - to make the hammers flexible, to dmap their fall, and to isolate the whole thing from the floor to cut down on vibration noise. Differentials rock! I was also inspired a lot by the videos on this channel I may try for a 2-octave verison if I can find a way to fit it around the xylophone...

Here is my latest creation. The mechanism is the same as my Synchropods, it is a mechanical implementation of this computer-generated version, and the motion is the same as the well known pendulum wave machine.

Ha ha ha - you are insane (in a good way)! It's great that you find a way to do it that doesn't require everything to be geared up first. At the heart of it, it looks like a very nice simple and robust design (the best kind). Looks like you've also done a great job with the structure and bracing. My guess is it could actually handle some load.

I don't think so - that's not how the torsen diff works. The worms with their inability to be back driven are the crucial aspect. They do of course want to slide on their axles - good bracing is essential.

Wow, this is absolutely amazing, congratulations! I LOVE this kind of machine. Not really that interested in "wheely" creations I am not sure I understand how you keep the blue "oscillating fork" in sync over the long term. Even if each movement gets reversed, if it is controlled just by timing via the orange clutch parts, won't the errors build up over time? Are the errors just small enough that in practice you can run it for hours without needing to recalibrate? Or do you have some way of keeping it in sync that I am not seeing?

Does anyone know if two of the new 1L worm gears will mesh with each other? The spacing would need to be weird, but this could reduce the number of high torque components. I can't check - separated from most of my collection by the virus

That's extremely interesting, great idea! Potentially you could increase the number of 8t gears, to spread the load. A problem with replacing the 8s with 24s is that it will triple the torque on those axles.

Yes, Oskar gets these things 3D printed by Shapeways. His channel is well worth checking out for ideas. He is perhaps the world's leading puzzle designer, but he has lots of interesting gearing ideas too.

This is brilliant! And almost certainly completely useless (this is also a compliment, coming from me! ). You asked TeamThrifty about other ideas. Have you seen Oskar van Deventer's billion-to-one gearing? There are some similar calculations involved (see the 2nd video). How about emulating that in Lego somehow?

And here's the 6-fold version:

Ha ha, that's brilliant! I wonder if this would be useful for spirographs? It reminds me of Synchro Pods, where I needed ratios of 80:81:82:83:84:85:86:87:88:89:90:91:92:93:94:95:96

I try to avoid 8t-8t meshing where possible - it does seem to create a fair bit of friction and stress. But if space is tight it could be an option.

The 12t bevel gears are just not suitable for high torque, even when braced properly. It would be better to redesign the assembly. There are plenty of more robust ways of reversing the direction:

That's brilliant! I love mechanical sensing, and I understand how much thought is needed to work in a confined space like this! I wonder about the long-term robustness of using axle connectors (in the sensing arm and in the little arm that holds the wheel in place at the bottom of the picture). They have a tendency to work loose...

A picture would be nice!

That's fantastic - can you show more details of the mechanism? Particularly the detent mechanism part on the right...

These are wonderful! The first two have quite a lot in common with Akiyuky modules, but of course there is no shame in that. The parallel motion linkage in the third one is fantastic!

Even simpler would be to replace the differential with a white clutch gear.