Davidz90

That's what I suspected. Knobs may be big, but in fact they have less slop than gears. Lego designers certainly knew what they were doing here.

Thanks! Hmmm.. what was the problem? Not enough power? The power consumption of various types of escapement mechanisms can vary greatly, from tens of miliwatts to tens of microwatts. Anyway, indefinite power sounds fascinating.

Wow, now that's a first post! Amazing! I love the brick-built livery and lack of any gaps in general.

Hi! Just wondering if anyone knows where and how will be the submitted photos/videos used? Curious what's gonna happen. What really surprised me, I got a thank-you gift from Lego (Bugatti Bolide set)

I have improved my calendar mechanism. First, I hevised a way to make a compact, 12-sided cam to encode lengths of months (by adding plates) cam_design_2 by David_Z1, on Flickr Then, I built the rest of the mechanism to match. Now it is way more compact.

After using better and flatter EM pickup that could be added without compromising the structure too much and reinforcing whole thing even more, I got better results:

Magnificent! I like this color scheme even more than original.

Yes, something like that. One structural issue to solve is the hole for pickup, which is not needed with piezo one; that part will need to be seriously reinforced, it was too flexible in previous guitars.

Yes, it is. I agree, I like the sound of earlier ones much more. I guess I'll go back to electromagnetic pickup and devise a way to handle the tension of two steel strings.

Thanks! I didn't know that rubber strings are a thing outside some toys. Yes, that could work well with Lego.

Absolutely, for some reason these pieces are a nightmare to attach. Not sure if it was always like this, or only recent ~2 years.

Absolutely amazing. Now I wonder how well X-wing or some other UCS series starships could be recreated with Lego technic without the limitations of being a B-model.

Another big update. Now the guitar has 2 strings! The key was to use piezoelectric pickup that can detect vibrations of nylon strings instead of steel ones. That greatly reduced the tension and also prevented bricks from getting damaged (steel strings were burrowing themselves into the bridge). Overall, it looks like this: over1 by David_Z1, on Flickr The piezo pickup is a little, handy device, normally attached to an acoustic guitar. Since I have no resonant chamber, instead it sits just below the bridge to get a strong signal. piezo by David_Z1, on Flickr To save space, tuning keys are on the back. This results in a very slim overall profile. keys2 by David_Z1, on Flickr There is a reinfoircing string on the back that acts as a truss rod. Its tension is regulated, so that neck angle can be slightly corrected. tension2 by David_Z1, on Flickr To get proper fret positions, I have written a computer program that found optimal guitar lengths, so that frets coincide with plates as much as possible. Black lines are ideal fret positions. Lego_Frets by David_Z1, on Flickr Finally, a video:

I guess it could be used to connect two chains side by side to make a thread. Also, it will be amazing for all sorts of mechanisms that use belts to encode something (mechanical calculators, calendar, all sorts of things that perform a sequence of motions/operations).

Wow, this pendulum has a surprisingly low friction.

This is exactly my case.

Thanks!

Yen another update - now the guitar has a proper fretboard. The downside is, apparently I'm even worse at playing this than a fretless one XD I will try to find someone who actually knows what he is doing to really test how much can be done with this design.

Indeed, pretty unusual and very impressive!

Thanks!

I hope it's okay to revive an old topic, but I have updated the guitar. Neck is now slightly thicker and stronger, electric components are actually soldered and shielded, which results in way less noise. Still needs some fine tuning.

Not only that, this large quarter ellipse will be amazing for all sorts of structural purposes. It should easily survive forces that would break a regular liftarm.

Me as well.

Amazing! 19.8 m/s is a very respectable number given the relatively small springs.

No, only active here and on Youtube. I considered buying a chronograph, but in the end measuring bolt drop and high-speed videos like here: https://www.youtube.com/watch?v=LamPgTpAIro&ab_channel=DavidZiemkiewicz provided accurate enough results. If I remeber correctly, springs were from garage doors; they had approximately 20 kg of pull each and it shows on slo-mo video - the crossbow really tries to shake itself apart :P There are few very nice design features of your crossbow, like the large pulleys; I used very small ones for strength, but at the cost of increased friction.