Sunday, 14 August 2016

Pneumatic system

The recently launched LEGO Technic 42053 Volvo EW160E proudly announces that it has "Pneumatic System V2" on the box:

However, anyone who has followed the Technic line for a time, will know that it is not the second Pneumatic System installment, it is in fact the fourth. See the four versions of the basic cylinder below:

With the observation that the Pneumatic System is often used to lift things, e.g., the boom of a construction vehicle, it is interesting to see this in a historic context. Here is how lifting has evolved in the Technic line:

1977: Rack and pinion

Technic itself was brand new in 1977, and the way to transform a rotational force into a translation (lifting) back then, was by using a rack and pinion:

This was used, e.g., in the 950 Forklift.

The downside of this method, is that the construction becomes quite fragile, and it is very complicated to get the geometry right. For a child to build a well functioning mechanism based on this principle is very hard, and can be demotivating.

To get the action more easily available, the first pneumatic system was soon introduced.

1984: Pneumatic System (first version)

In the first pneumatic system, used in, e.g., 8040 Universal Set, the cylinder was single acting, i.e., it had only one connection for the air hoses:

This required the special 2x4 valve pictured above, which turned the blowing force from the pump (left) into both blowing and suction, as decided with the toggle valve. It worked well, and made it much easier for a child to make powerful lifting booms and similar constructions.

As long as you can get an air hose out to the cylinder, you can place it pretty much anywhere you want on a model, which makes it very flexible and fun to build with.

1989: Pneumatic System (second version)

Already after five years, the pneumatic system was superseded with a second version. Now, the cylinders became double acting, i.e., they had two air hose connections each. This means that the special valve which creates the suction air stream is no longer needed, but the downside is that you need to connect one more hose out to each cylinder.

It was used in, e.g., the very big and complex 8862 Backhoe Grader.

A smaller cylinder, and also a mini-pump were later introduced, as this system lived for a long period. The mini-pump had an odd geometry, making it hard to use effectively in a model: It was not an exact stud unit length neither at the shortest, nor the longest extension.

1991: Flex System

The flex-system was introduced in the 8856 Whirlwind Rescue helicopter, as an alternative way to transfer energy from one place to another in a model.

As the name suggests, it is quite flexible, however, you must have a hose and a "wire" with exactly the length you need to fit when making your own model, which can be frustrating. So this system works well with some official sets, where you get exactly the right lengths, but it is not so easy to use in your own creations.

1995: Worm Gear and Liftarm

The worm gear appeared already in 1990, but it was not until 1995 that it was used for lifting. The special yellow gear box below made it easy to create a boom like creation:

This also introduced the liftarms, a harbinger of the soon to come studless Technic system. They are often called liftarms, because they use the rotational force from an axle to lift something connected to the other end. An example 1x4 liftarm can be seen in grey above.

It was used in, e.g., the 8280 Fire Engine. Even if the gear box is not commonly seen today, the same technique has been used in countless Technic sets over the years, and is still widely used these days.

Personally, I'm not a big fan of this construction technique. I don't think it is realistic: This it not nearly like how real machines work. Hence, I think it is not in line with the "As In Reality" Technic slogan.

2008: Linear Actuator (61927)

Used in, e.g., the 8295 Telescopic Handler, the Linear Actuators became an alternative to the Pneumatic System. Like the Pneumatic System, this also looks like real life hydraulic cylinders, in line with the "As In Reality" slogan:

Just like the original rack and pinion systems, however, there is the problem of getting the rotational energy out to the cylinders in the first place. This can be tricky, even if LEGO does supply some specially made brackets for this purpose:

The bracket for connecting a bevel gear (top), is the most common, and is in, e.g., 42043 Mercedes-Benz Arocs. The bracket for connecting a motor (bottom), is very rare, and has only appeared in two sets. Most recently, the 8264 Hauler in 2009.

Take a look at the 8043 Motorized Excavator for an example where axles bring the rotational energy out to a three segment excavator boom. This is immensely complicated. Building something similar in your own creation is hard even for an adult.

Looking at the years in the timeline, it can appear that there was not a lot of innovation in LEGO Technic around the turn of the century. It is common to say that this was a low period for LEGO in general. However, keep in mind that this was the time when the Mindstroms sets were developed, so in fairness there was certainly innovation in the Technic line.

2011: Small Linear Actuator (92693)

In the 8069 Backhoe Loader, a smaller linear actuator was introduced.

2011: Pneumatic System (third version)

Just when people thought the linear actuators had replaced the pneumatic system, a third version is included in the licenced 8110 Mercedes Benz Unimog:

This systems marks the transition to the studless building technique, as it is no longer possible to connect the cylinder to a traditional brick.

Also, the mini-pump now has a more sensible geometry, making it much easier to build into your own creation. There is a two stud unit length between minimum and maximum extension, so you can power it with a rotating 3x3 wheel.

2015: Pneumatic System V2 (forth version)

Finally, with the LEGO Technic 42053 Volvo EW160E, we get a new revision of the Pneumatic System:

This takes the final step into the studless system, in my opinion, as the width of the connection is now only one stud, not two as before (new cylinder to the left below):

Another innovation, is that the air hose connection has a narrow tap, making it easier to attach a hose (new to the left below):

Other than these changes, the new system is much like the previous installment. There is now a better colour coding: Blue cylinders are pumps, yellow cylinders do the action.


I think the reintroduction of the pneumatic system makes it clear that LEGO understands the challenges with the competing linear actuators: They are very complex to use in your own creations. The pneumatic cylinders, on the other hand, can be placed pretty much anywhere on a model, and you don't need to worry about getting a gear train out to power it.

Using pneumatic cylinders, it is easy to create models with powerful action quickly, even for children. Which is what LEGO Technic is all about, anyway.

Monday, 25 July 2016

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:

Sunday, 18 October 2015

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:

Monday, 19 January 2015

Lego caricature

Lately, caricatures have been all the rage. Using the headpiece from the snake charmer character (from minifigures series 13) and the beard from the Wiley Fusebot character (from minifigures series The Movie), you can make your own LEGO caricature:

The torso comes from a a LEGO star wars jedi character, I think.

The picture was taken using the Lumix GH4, the Leica 45mm f/2.8 macro lens, and the Lumix FL360 flash gun. I used a transparent bucket as a cheap and simple macro soft box.

Saturday, 3 May 2014

"Brent av frost"

The Norwegian movie Brent av frost (1997) is famous for having a scene where a couple makes love in a boat full of fish. With LEGO having both boats and fish, this scene is of course possible to recreate:

The actor, Gørild Mauseth, made a deal that the scene would never be shown out of context. She later took a broadcasting corporation to court when they did show the scene on national television, since it had recently been parodied in the movie Kill Buljo. She won the case.

In the start of the scene, the actor cuts a fish open, and lets the blood drip on her body:

To photograph the scene, I used a transparent bucket as a simple macro softbox, for more even lightning. I used the Leica 45mm f/2.8 macro lens, and the Lumix GH3 camera.

Wednesday, 5 March 2014

Clamshell grab for cranes

Grabs are fun. Here is a simple clamshell grab which uses the scoops from, e.g.,
42023 Construction Crew, or 8069 Backhoe Loader. It can be operated manually, or by a motor.

Tuesday, 30 April 2013

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: