JoKo

I rebuilt the drums module. It uses now only one track so it can be twice as long. It has 5 "arms " playing 4 different drums. The rhythm precision seems ok, it sounds fine but the bass drum (digger bucket 15x23) doesn't sound low enough to my taste. With a little bit of sound editing I can make it good enough so I'll keep it like this and focus on the next step: automating the harpsichord which requires 8 actuators and is more sensitive to mechanism noise. There is an example of the drums sound natural and edited.

Thanks, It's great for me to mix Lego Technic with music because I love both. Those are fishing lines... I tried nylon guitar strings mostly to have lower notes for playing a bass line. I faced the same issue as you, the frame is not stiff enough, bends and the keys get too much friction. That's the main improvement I want to make. I should build the frame like a piano, not like a guitar.

So the guitar/harpsichord evolved . It is now a double neck (double decker) with 8 strings and 8 key to play it. It works with small "claws" and a rubber piece to mute the strings that are not played. I would need to build the frame more rigid, it bends if the strings are to tight and it induces too much friction in the keys mechanism. I'm however confident that it can be automated. It will be the main feature of the machine. I don't quit the gear-diaphragm-gearbox system but I will have to simplify it back to 3-4 notes and not rely on this to play actual music.

New update: OK, the piano mechanism was not a good idea. It is so noisy and still doesn't make a string that loud. Pinching a string on the other hand has potential. I made a basic "guitar" and worked on a mechanism that can pinch a string and mute it. It works quite well. Sounds as good as a 5$ ukulele that gets out of tune in 3 minutes but I can tune it and now I am more confident that my machine will be able to play music, not just rhythm and noise

Thank you! Since the gearbox-gear-diaphragm is very hard to tune and can play only one note at the time I am studying piano mechanism. Since custom string are allowed it seems the obvious way to go if I want some audible music I copied the mechanism from this video and simplified a little bit https://youtu.be/uBEL3YVzMwk?si=CAfAnVwGbB7SCwlO

Yeah, 100% LEGO pieces is part of the contest rules. Custom string is hovever allowed so I might experiment with that too Thanks! I never heard about it before but I just discovered it is basically the ancestor of the Hammond Organ. Which is what inspired me so I was actually inspired by the Telharmonium

@LegoTT @2GodBDGlory Thanks! I did never see that. but good for insiration, thanks. Actually I was inspired by Wintergatan's marble machine : https://youtu.be/IvUU8joBb1Q?si=n_Wkwl-CxUkNGvXd Update : Motor : Upgrade to 2x Control+ XL with double planetary primary gearing Gearbox : I upgraded to 8 x 2 speed. 8 chromatic speeds and a secondary 2 speed gearbox between the keyboard and the "speaker" Horn / speaker : I mounted the diaphragm and the pitch wheel to the base of the horn. I now have a "speaker" with easy assembly. Also sound is louder. Drum / Automation : I dug a never-finished prototype out of the graveyard. It was a red octopus playing drums, I quit it because it needed deep rethought but for this project it is "free" R&D . I want to change the track system to one track only ( 5 drums are enough) and I will need two tracks to automate the keyboard. New gearbox : New keyboard : Full organ : Automated drums module :

It looks very good for now! The engine looks perfectly Ducati

Nice! I think it's the icing on the cake. Makes your version so much better than the official 1200GS with this gearbox, acurate boxer engine and the other visual fix you made. Thanks for the gearbox details!

Let's share random ideas for TC28 ! Industrial : Braiding, knitting, sewing machine, mechanical loom, steam engine, windmill (classical or innovative), drill press, lathe, milling machine (should be able to machine some polystyrene with lego) Musical : functional guitar , metronome Weaponry : crossbow, revolver , catapult , trebuchet , DCA turret , nuke... Space & Stars : deployable satellite , astrolabe, celestial navigation device (sextant require mirrors but other solutions are possible), Solar system model , flat earth physical model

@Davidz90Thanks for the encouragement! I tested with stiff pieces instead of the windscreen like flags or minifig shield. tested the windscreen curved also. current solution is the loudest and most forgiving, not the best sounding. I still have plenty of time to try other thing like dome windcreen as resonator and so on... may also include some kind of clock escapement mechanism to help keeping a steady speed at the gearbox input. Thanks!

I have a few fake engines prototypes on the shelf that could be great for this contest but I think this theme is a excellent occasion to try something different, if possible never seen before. I will therefore try this crazy idea first. It could be described as a Gearbox Barrel Organ. It borrows ideas from the Hammond organ, the barrel organ and the gramophone. Working principle: A flexible tab (reed) touching a rotating gear vibrates and create a note noise. If the gear speed increase, so do the noise pitch. So in theory a well-designed gearbox should be able to turn this noise into some kind of melody, right?... let's try! Gearbox : I first tried to play harmonics like major third, fifth and octave (gearbox ration: 1.25 , 1.5 , 2) The notes were discernable but it is limiting the possible melody. And the gearbox only works one note at the time so no chord is possible. It basically sounded like a bad alphorn. I faced another problem: the reed needs different setting for low or high notes so I had to narrow the notes range. Currently gear ratios are: (1 , 1.125 , 1.2 , 1.25 , 1.33 , 1.5) and it should sound like : A , B , C , C# , D and E Keyboard : It is a quite simple keyboard that activates the dog rings. It features a flywheel to minimize speed variation when notes are played. As i have no keyboard player talent I'm planning to make a music box mechanism instead Horn : In order to amplify the sound I build a flared horn with brassy colors, It has a 42107 Ducati windscreen as diaphragm or reed that makes contact with the 40 th gear at the keyboard output. Of course I can't demonstrate it without a video. Don't expect too much.... it sound weird and bad... at least for now!

I love this one! Great job with the gearbox and boxer engine. This allows the engine to be a real "boxer" with pistons moving in opposition. I'd love to build it. Are you thinking about making a studio model or a video to show the gearbox in action? Also may I suggest a slight modification in order to ad a realistic detail? On every BMW boxer engine the cylinders are offset because of the boxer crankshaft. The left cylinder is ~50mm in front of the right one. Most people never notice it because it is rarely visible on pictures but when you happen to have one between your legs it is obvious. You could add a 1/2 stud offset to your design like this: Right cylinder: Left cylinder: Together:

Was it to promote creativity or for some legal/moral reason?

Now that my animal-human as been set aside I am thinking again about an engine and am facing this question: The engine I have in mind is very typical of a well-known brand. Is it OK if I just don't mention that brand?

OK Let's keep the humanoid ideas for the animal contest I also thought about musical machine, I made a first prototype a few month ago and didn't figure out a way to make it 100% lego.

But no head or any other human-related appearance? is that what you mean?

What about a robot static automaton (exemple: it looks like Wall-e without tracks) that perform some action with arms?

I considered building a large scale fake engine but I thought it was too much vehicle-related. I don't think it's against the rules though. Philosophical question: I'm thinking about a humanoid static automaton. Does it violate the new no animal rule?

@YappilandYou're welcome! This solution could work too. These gears will work just as well! Not sure about the frame but it's worth trying.

I found this: It should work with your wheels too. If you don't have a differential stop the video at 3:20 and build this instead (then back to video at 3:34)

You would be surprised @bruh If you want to build a pop-up town fairs ride maybe just make it unfold from static base.

Ok I'll see what I can do. But I didn't understand exactly what are the electronics you own. Can you be more specific about that?

OK so what size have you in mind? Have you an idea about the wheels you want? The steering system of the McLaren is indeed simple and you can easily connect a servo on the steering axle You can also take inspiration on the McLaren to motorize your car. You can connect the motor to the rear wheel instead of the V8 fake engine. Did I answer your question? I can help you with building a chassis but i need to understand what you have in mind.

Yeah, I know it is still vague. What I meant is a four legged mech with boxy shape is not allowed. It has to feature some "animal" mechanism like moving head, mouth, tail...