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Posted

TECHNIC NON-VEHICLE CONTEST - ENTRY TOPIC

CONTEST INFORMATION

More information about the contest can be found in the general discussion topic.

WHAT DO I NEED TO ENTER?

Please take a careful look at the rules before posting in this topic. Each participant is obliged to create a post in this entry topic. Posts need to follow the rules stated below. Posts not following the rules will be disqualified so please read them carefully.

ENTRY POST

The entry post in this topic needs to contain:

  • Entry name
  • Short summary of the functions.
  • One or more images (max 4).  You can have combined pictures (4 in 1) as long as the picture isn't bigger than 1024x1024.
  • Embedded Youtube video (not mandatory)
  • Link to the discussion topic

IMPORTANT

This topic should be used for entries only, so commenting is prohibited. Please use the general discussion topic for...well, general discussion on the contest, and individual discussion topics to comment on the individual entries.

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  • Jim unlocked this topic
Posted (edited)

ROCK MACHINE

“ Vehicles move your body, Rock'n'Roll moves your soul. “

 

This Machine is some kind of complex music box that can play "drums and guitar". It is made up of a music box mechanism and a removable music instrument that can be played manually on its own. This instrument is technically a harpsichord as it plucks strings when keys are pressed. It is a small harpsichord though so I named this instrument the "Harpy"!

Mechanical and musical features:

  • 8 strings harpsichord (Harpy) with boat hull as sound box (https://www.bricklink.com/v2/catalog/catalogitem.page?P=30215pb01#T=C&C=1)
  • 128 lines loop harpsichord automaton
  • 128 lines loop automated drum kit with kick (loader bucket), tom (red rim), snare drum (silver rim) and hi-hat (batcycle rim)
  • Pneumatic mute system (drums and strings) with manal pump, two air tanks, pressure gauge
  • Bar counter display (with coaxial counter-rotating fan)
  • Adjustable drum-strings synchronization ( with differential and worm gear)

Visual details:

  • Red mystic spiral (hypnotic)
  • Turbos (why not?)
  • Minifig scale stage with automated lightshow
  • Fake electric guitar 

Dimensions:

  • Machine 86 x 86 x 24cm
  • Harpy: 60 x 43 x 13cm

Impressive numbers:

  • This is the height of absurdity for a static non-vehicle but it uses 384 wide track links, eight 24mm wheels, eight 14.5mm tires, 3 turbos, two motorcycle rear wheels (1:5 and 1:8 ) and a cooling fan!
  • The theoretical number of different "song" it can play with 8 notes is 3.9*10^115 (drums not included)

Pictures:

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IQT48Aw2wd3xQJCk1ZSX0eiSAVvIjnyKpybnaMph

 

IQTay0mivEVuTaCvSg4RajYqAXQIjJbyfLERGDb1

 

IQSH6MNizt26TbvG7SwDizQMAcDvEqXt8CZQOd-t

 

Video:

The LEGO Rock Machine has it's own YouTube channel. Videos that are not linked here may not respect TC28 rules.

 Money for Nothing (Dire Straits cover):  https://youtube.com/shorts/gHf9a6g1c2A?feature=share

Cowboys From Hell (Pantera cover): https://youtube.com/shorts/4YSeqxyaCKA?feature=share

 

Presentation video: 

 

Discussion topic:  (more pictures on page 2)

https://www.eurobricks.com/forum/forums/topic/200688-tc28-rock-machine-musical-contraption/page/2/#comments

 

Edited by JoKo
video
Posted

"Suspense" - abstract balance wheel clock

Unlike 99% of all Lego clocks, this one uses a balance wheel oscillating back and forth, like in a wristwatch. Moreover, to make it even more unique, it consists of 3 separate parts connected by a chain loop.

54338623100_c53de019d0_c.jpg

It all started from the idea to use Indiana Jones whip as a suitably weak spring and a ball pin as a low-friction bearing. The whole combo is still nowhere near as good as a pendulum, but can serve as a rudimentary oscillator.

54222790169_9ac6c9b0a4_c.jpg

The top piece contains the escapement mechanism.

54338229141_4ceebe7dc4_o.jpg

It is a so-called chronometer escapement. It delivers a short, strong push to the wheel every time it passes the middle point where the whip spring is not twisted. At this magical point, applied force doesn't alter the period (math behind this is fascinating, but a little beyond the scope of this topic :) but here's a simple explanation with a pendulum example: pushing the pendulum forward on its way down helps the gravity, so pendulum speeds up. Pushing the pendulum on its way up fights the gravity, slowing it down. Pushing it in its lowest point does neither). Only thanks to that fact, I could get any semblance of accuracy with a balance wheel that has a low efficiency compared to a pendulum, so the pushing force needs to be rather high accordingly.

Middle part is auto-rewinder that doubles as a driving weight. It is hanging on the left chain, climbing it periodically so that the whole chain loop rotates counterclockwise. It uses a system of levers to apply sufficient force to on/off switch without affecting the clock too much.

The face hangs at the bottom, hands are moved by the cycling chain loop.

Stats:

The balance wheel is very power hungry, auto-rewinder has to activate every 5 minutes or so. Long-running clock without autorewinder seems impossible. Spring power is impractical as well.

The most important goal was to make this clock accurate, and I managed that. The average period was 2.0012 seconds with target of 2 seconds, which is 0.06% error. This means that the clock will be off by about one minute after a day of working. Short-duration runs confirmed this, showing about 1 second of error after 30 minutes (so 48 seconds in a day):

54293303184_8d3237afae_w.jpg

These short runs were analyzed by recording the ticking sound and running the file through a computer program I wrote to calculate all individual periods. I also did some longer tests, which were slightly less impressive. A 6 hour run ended up with 47 seconds of error, indicating that about 3 minutes/day is a more realistic estimate. A big problem is temperature stability - not only thermal expansion changes the inertia of the wheel, but the elastic properties of the whip change with temperature too. In wristwatches, a lot of research goes into new, exotic spring materials to combat just that.  

 

Video of the clock:

Link to the topic:

 

Posted

Pendulum Clock

"Time stays long enough for anyone who will use it"
Da Vinci

Functions:

  • Time accurate seconds, minutes and hours hand including AM/PM hand (0,17% deviation per 4 hours)
  • Robust escapement system with escape wheel and anchor with top and bottom pallet
  • Auto rewinding driver weight with Power Functions
  • Pendulum with elevated pivot point and adjustable top and bottom weights for time calibration
  • Chime sound by Zamor Sphere drop every hour, includes ball targeting gate and sound tile
  • Easy accessible and removable battery box with on/off switch
  • Sturdy frame with sound dampening feet
  • Roman numerals with intervals

Below the picture the final video including a 12h Timelapse.

LEGO Technic Clock

 

 

 

Posted (edited)

The Marvellous Mechanical Date Engine

(automatic perpetual calendar)

  • Determines the day of the week of any date in the time period 1601 - 2300 (in the modern Gregorian calendar)
  • Automatic correct treatment of leap years, including the special 100- and 400-year rules. (This is in contrast with all other hand-calculation methods and physical perpetual calendars that I am aware of, all of which require some kind of manual adjustment for leap years)
  • Simple intuitive operation
  • Four hand-operated knobs to select date, month, century and year
  • Positive, precise switching, with no ambiguity of results (achieved by a combination of spring and gravity detent mechanisms)
  • Three differentials perform the calculation 
  • Modular construction, making for straightforward set-up and adjustment

Dimensions: 35x20x20 cm

Parts: approx 1300

  800x713.jpg

800x625.jpg

800x399.jpg

800x514.png

Discussion thread:

 

Edited by aeh5040
Posted (edited)

Pneumatic hexapod:

Hello everybody,

among other things, the company I work for uses a hexapod for vibrational and fatique analysis of car parts like hood, doors, interior, etc. A hexapod can control all six degrees of freedom of the tested device, which allows you to recreate various driving situations and loads without the need of the real car.

This contest inspired me to recreate such a device in lego. Whilst obviously switching from hydraulic to pneumatic, everything else should be as realistic as possible. This meant, that unlike other lego-hexapods out there, I had to go for stationary cylinders. (You do not want moving cylinders in vibrational analysis due to inertia and damping effects of the cylinders, as well as wear on the hydraulic hoses)

The most difficult part was to get the angles of the cylinders right so the table can have a maximum of movement without the cylinders and the linkage getting in the way of each other. 

 

Hexapod 1

 

Hexapod 2

 

Hexapod 3 Hexapod 4

 

It is a rather small construction compared to some of the other awesome entries, but I wanted it to be focused on the core functionality.

Best regards and good luck to everyone. 

Edited by n8walker
Pictures and description
Posted (edited)

Mecanical PONG arcade machine

Function

Mecanical 'ball' moving using one PF XL motor

2 speed game speed

2 player paddle

KakaoTalk_20250224_224822696.jpgKakaoTalk_20250224_224822696_01.jpgKakaoTalk_20250224_224822696_02.jpgKakaoTalk_20250224_224822696_03.jpg

 

Edited by msk6003
Posted

Oil Pumpjack 

This is my first time participating, and I didn’t notice that I needed to duplicate the application here.

Description of the functions:

1. Horsehead, Beam, and Crank-Slider Mechanism: The main element of the structure consists of a beam connected to a horsehead, simulating the rocking motion of a real pumpjack. The crank-slider mechanism converts rotational motion into linear motion, creating smooth and stable oscillations of the beam.

2. Counterweight: The counterweight stabilizes the movement of the entire structure, maintaining uniformity in the beam’s rocking motion, making the mechanism more efficient.

3. Electric Motors(2L): These drive the entire mechanism, automating the rocking movements.

4. Power Supply: The battery pack is placed in the form of a transformer booth, and power lines supply energy to the motors, imitating the real power supply to an oil pumpjack.

 

 

https://www.eurobricks.com/forum/forums/topic/201535-tc28-oil-pumpjack/

 

54339164576_50b6ced973_b.jpg

  • Milan locked this topic
  • Jim unlocked this topic
Posted

Metal lathe

Unfortunately my entry was far more complex and difficult thing to build than I had anticipated, so my entry is barebones and missing some of the features I originally planned. The implemented features include:

  • Spindle on ball bearings
  • Motorized with 9V train controller for multiple speeds in both directions
  • Thread cutting gearbox with 4 speeds and direction switch
  • Motorized longnitudal feed
  • Manual traverse feed
  • Self-centering chuck with three jaws

GriQG71.jpeg

 

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