Lego Automata: Two hand rude gesture

An automata, or a kinetic sculpture, is usually a decorative item which moves in some way. Popularized some hundreds of years ago with clockwork like mechanisms, they can more easily be made today using Lego Technic bricks.

Here is a kinetic sculpture which shows the somewhat rude two hand gesture, where the index finger of one hand is passed in and out of a loop formed by the thumb and index finger of the other, suggesting coitus.

At the same time, the whole contraption also rotates, as you can see in this video:



The hand itself is made mostly out of fairly common bricks and plates:

The most used special plate is the 1x2 plate with handle (60478). Each finger uses three of them:

I got these parts mostly from the Mixels Busto set, which has six of them each. The hand can be posed in a fairly realistic way:

Not so visible in the video, but the base of the contraption is made with rubber wheels as "feet", to make it more stable. The motor powers both the rotation and the contraction of the yellow arms. The motor output is geared down 1:8 using a worm gear and a z8, and the 8:56 as the z8 (8 teeth cog) meshes with the outside of the big turntable:

Build a LEGO DOMO!

Domo is the official mascot of Japan's broadcaster NHK. The big mouthed character is normally portrayed in brown, but I didn't have enough of that colour, and decided to go for light grey:

The teeth are important for the looks of this character. I used the 1x2 plate with three teeth, often seen in the LEGO Mixels sets, e.g., the 41545 Kramm and the 41537 Jinky.

Domo has four teeth in the upper and lower jaws, but the part only has three. Still, I think the three teeth part is good enough to make a recognizable Domo figure.

Ideally, I would have preferred some black, round, beady parts for his eyes, but at this scale, I couldn't find any good options. So I just made holes for his eyes. The holes are made by using a 1x2 jumper plate (with a central stud) for a half unit offset.

From the rear, you'll see that I have used a 4L bar to connect the legs. This looks rather odd, but it does allow for a bit of articulation of the legs:

I made the legs separate like this to get the right shape of the body when seen from the front. Do you think you can improve upon the leg design? Why not give it a try!

Here is how I made the figure. The parts for the limbs are on the right hand side, and the two 2x4 tiles are to cover his back:

Note that I am using a 1x1 brick with technic hole, and the blue pin. But that is just because I didn't have enough 1x1 bricks with stud on the side. So if you have the 1x1 bricks with side stud, use that rather than the technic brick.

Also, you can replace the two additional technic bricks with normal 1x1 bricks. Again, I just took what I found first:

The two red 1x2 tiles will become his mouth:

The red 1x2 brick has studs on both sides:

When all is done, connect the two 2x4 tiles to the red brick on the back to cover up his internal organs:

LEGO Technic useless machine

In popular mechanics, a "useless machine" is one that does nothing beyond turning itself off again. When made in LEGO, you will often find them powered by a motor, by gravity, or by some other means. When I saw the new wind up motor in the LEGO Technic sets 42033 and 42034, I knew it could be used to power a "useless machine".

The only disadvantage of using a wind up motor, is that it runs very fast. It easily reaches a high speed, as long as the friction is low. To overcome this problem, I put a clockwork escapement mechanism into the machine, to limit the speed of the motor when the device is running. Here is the result:

Geneva drive in Lego Technic

The Geneva drive is a mechanical device that transform a smooth rotation into an intermittent rotary motion. Traditionally, this has had applications within watch making.

The Lego mechanism showcased here transfers one rotation of the drive axle into 1/4 rotation of the output axle. Here are the basic movements explained.

The driving axle (to the right) locks the output axle, due to the black half circle shape.

Helicopter rotor with cyclic control

In 2012, LEGO released the 9396 Helicopter model. While this is a good set, with realistic looking helicopter blades, the blade operation is still far from realistic.



The model includes collective pitch adjustment for the rotor blades. The word collective in this case refers to the fact that the pitch of all the blades change at the same time, collectively. This is all well, however, not really anything new, since this feature was also included in the 852 Helicopter model from 1977!

The key to the success of the helicopter is the cyclic rotor pitch adjustment, usually operated through the pilot's stick. This involves having a swashplate below the rotor, to which there are rods connected to the rotor blades. The rods control the pitch of the blades. As the swashplate is tilted, the pitch of the rotor blades change cyclically through the rotation. This animated GIF explains how the a tilted swash plate affects the cyclic blade pitch:

Animation made by Richard Wheeler (Zephyris) for use in Wikipedia, and uploaded using the GNU Free Documentation License

In the animation, the disc below the rotor is the swashplate.

Lego Technic 4x4 skid steer loader

Here is a video demonstrating the model. In the rest of the article, I will describe the design choices and design challenges with this model.