LEGO Technic Tora no Maki is a new book by ISOGAWA Yoshihito and is available on the internet for download. He asks $10 to be paid, which is more than a fair price as this book boasts over 200 pages of images of over 1700 LEGO constructs.
Here is a sample page:
Download it from:
http://www.isogawastudio.co.jp/legostudio/toranomaki/en/
And don’t forget to pay the $10 if you can afford it.
All of a sudden there are several NXT books available. Here are several that I have seen and really enjoy.
The others, I have not yet had a chance to review.
At times one may want to control the transmission of rotational motion by engaging or disengaging an axle from a motor. Such a mechanism is called a clutch.
LEGO has special parts that can be used to make a clutch. However, these are relatively hard to find, and take some force to engage or disengage.
Many clutch designs simply move gears back and forth across one another, but this causes the gears to grind and eventually wears down the parts. In these systems, the clutch does not engage smoothly.
I was aiming to design a clutch that can engage or disengage with very little force, while also being made of common parts. Below is my most recent design which relies on the easy meshing between two pin with towball pieces on the 24 tooth gear and the Technic connector with axlehole on the central drive. The only parts that are less common are the two Technic disks with axlehole. These can probably be replaced with other parts. Perhaps axles extending from the lever would work.
Here are the instructions in pdf format, as well as a zip file containing the LDraw files.
The following animations demonstrate the basic mechanism:
This one shows the coupling mechanism in detail from below:
I will post a description of how I made the animations.
Note that the engaging lever even pauses until the coupling mechanism meshes with the towball pins.
This mechanism can be powered with a motor coupled to a differential. This enables one motor to control both the drive and the switching. Rotating the motor in one direction will switch to one side and drive it, while rotating the motor in the other direction will switch to drive the other side. I will post a detailed description of how to do this as well.
Hexagonal platforms are easily created using any one of the equilateral triangle designs. Here is an image of a large hexagon. In this graphic, the triangles are not connected, but this is easily accomplished using plates. Two 2×4 plates per connection would suffice for most purposes.
LEGOs are designed to go together to form rectangles. Here I present some possibilities for equilateral triangles, which can be extended to form hexagons. Some of the more recent triangle designs, which I present below are being used in a current design for a tri-wheel drive system for a Mindstorms rover I am currently constructing.
These first triangular designs are equilateral triangles (same side lengths), and can be put together to form hexagons as well. These are extremely sturdy constructs and may find use in triangular or hexagonal bases.
Below is the smallest LEGO equilateral triangle. The parts used to construct it are shown to the right. It often takes a bit of pressure to snap this together since it is a tight fit, so take care when doing so.
One can make equilateral triangles of any size this way.
If the connectors are a bit cluncky,
one can use the thin technic liftarms with the small axles to secure the triangle.
Here is a rotating image of the result so you can get a good look.
The two following designs are slightly alternate forms.
One uses beams of length 11, but is offset slightly so that there are empty peg holes at the corners of the equilateral triangle.
The following design uses beams of length 9, and lacks holes at the triangle corners.
The following triangle is composed of beams of length 11, and has a a 3-blade rotor in the center to act as an axle. The parts list and instructions can be found here.
An animated version illustrates how the braces hold the central rotor in place.
It can be very difficult to figure out exactly how to store one’s LEGO parts. This depends greatly on the extent of your collection, and how mobile it needs to be. Below I offer a wide array of suggestions ranging from the size of one NXT set through tens of NXT sets with thousands of dollars of extra parts. Here I will review the solutions that I have found useful, and at the end I will provide a detailed description of my particular storage strategy.
, which provides an excellent means of both storage and transport.The new Custom Divider Systems (CDS) give you a great many ways to divide each box into bins with the greatest versatility. The other divider systems work well, but this is a nice option.
| Small Box Plano No. 2-3500-20 9-1/8″ Wide. x 1-1/4″ High x 5″ Deep Up to 9 adjustable compartments Order from Amazon.com These fit into the Plano 1354 Tackle Box  below |
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| Medium Box Plano No. 2-3650-20 11″ Wide x 1-3/4″ High x 7-1/4″ Deep Up to 18 adjustable compartments These fit into the Plano 1364 Tackle Box below |
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| Large Box Plano No. 2-3750-20 14″ Wide x 2″ High x 9-1/4″ Deep Up to 20 adjustable compartments These fit into the Plano 1374 Tackle Box below |
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| Plano 1354 Tackle Box (3500 size) I have found that the 1354 Tackle Box is a bit on the small side for even the smallest collections. You will be surprised at how many distinct kinds of Lego parts there are, when you find that they will never fit into the 9×4 compartments. However, this tackle box can hold 4 utility boxes, and you often can put an additional box in the top compartment. Order at Amazon.com |
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| Plano 1364 Tackle Box (3650 size) This is a really nice size for a tackle box. I can easily store at least two NXT sets in this tackle box as well as many extra parts. Four Plano ProLatch 3650 stowaway boxes  fit in the tray resulting in 4×18 = 72 compartments. I also manage to keep an additional 3650 box in the top of the tackle box. I can often work with just this subset of my collection. In addition, it makes travel easy. Plano 1364 Tackle Box at Amazon.com |
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| Plano 1374 Tackle Box (3750 size) This tackle box can hold a large number of parts. The top bulk storage compartment is sufficiently large and deep to actually hold smaller robots! The 3750 size utility boxes are very spacious, and this tackle box comes with one of the newer Custom Divider System (CDS) utility boxes, and one flip-sider, which is good for fishing tackle, but not so useful for LEGO parts. For this reason, you may need to buy an extra 3750 box to replace the flip-sider. And you may want an extra 3750 to fit in the top compartment. Plano 1374 Tackle Box at Amazon.com |
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Akro-Mills 10724 24 Drawer Storage This organizer can hold a healthy supply of small LEGO parts. The organizer comes with partitions that can be inserted into the drawers allowing one to keep more parts.Overall Size: W=20″ H=15.81″ D=6.38″ (inches) Drawer Size: 4.25″ W x 5.25″ D x 2.0″ HI have three of these. One holds all of my pins and connectors. The second holds all of my axles and axle connectors, and the third holds all of my gears. |
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| Akro-Mills 10124-2 44 Drawer Storage This organizer can hold a healthy supply of small LEGO parts. The organizer comes with partitions that can be inserted into the drawers allowing one to keep more parts.Overall Size: W=20″ H=15.81″ D=6.38″ (inches) Large Drawers: 4.38″ W x 5.25″ D x 2.0″ H Small Drawers: 2.13″ W x 5.25″ D x 1.50″ H |
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Akro-Mils 10764 64-Drawer Storage This organizer can hold many small LEGO parts. The organizer comes with partitions that can be inserted into the drawers allowing one to keep even more parts.Overall Size: W=20″ H=15.81″ D=6.38″ (inches) Small Drawers: 2.13″ W x 5.25″ D x 1.50″ H |
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| Three Drawer Organizer I have found the Sterilite ClearView™ Wide Three Drawer Organizer 2093 to work very well. Its dimensions are suffciently large to hold a large number of brick. Or one could make partitions (they do not come with the drawer) to store a wide array of parts in a single drawer. At this point, I use 20 of these to store my bricks, plates, liftarms, wheels, and specialized NXT parts. The clear drawers make it easy to see what is inside, and one can easily afix large easy-to-read labels.The dimensions of the three drawer organizer is: 14 5/8″ L x 14 1/2″ W x 10 5/8″ H. |
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| This tool chest when packed full holds: 4 large Plano 3750 compartment boxes 3 medium Plano 3650 compartment boxes 6 small Plano 3500 compartment boxesThis is in addition to the large top tray that can hold Mindstorm NXT bricks, a great deal of cabling, and other tools that you might need.The tool chest has a handle and wheels, which makes for easy transportation. Order from Amazon.com here. |
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See the more recent posts: COLORFUL LEGO STORAGE IDEAS and New LEGO STORAGE OPPORTUNITIES for more ideas.
The Geneva Mechanism takes smooth rotary motion and converts it to intermittent rotary motion. One can think of it in electronics terms as changing the duty cycle of the oscillation. This is a mechanical version.
Geneva mechanisms were invented in Switzerland for use in clockwork so that the hands of a clock would snap rapidly to their new positions rather than move smoothly across the face of the clock. They are also used to advance movie film in film projectors and are responsible for that clicking noise that film projectors make.
Here is a rendering of a Geneva Mechanism designed from LEGO parts. This rendering was made using MLCad in the LDraw package in conjunction with L3PAO and POV Ray. Below the mechanism in operation. This process will be described in detail in a future post.
The building instructions are straightfoward and can be downloaded in this zip file.
I am looking into using such a mechanism in a LEGO laser scanner, which can be used in instrument or robotics applications.
A smaller LEGO Geneva Mechanism created by Leo Dorst of the Intelligent Systems Laboratory in Amsterdam can be found here, although I have not been able to get it to work myself.