3-D Joint

Matthias Paul Scholz published building instructions for a joint with two turn tables orthogonal to each other. Two motors allow for stable and precise movements in three dimensions of a payload attached on the top.

A 4-Wheel Drive, 4-Wheel Steering Vehicle with Suspension

Building a 4-wheel drive vehicle with steering always seemed like a difficult challenge to me. A few days ago I came across an interesting and compact design for a pendular suspension (thanks to TechnicBRICKs for highlighting this design). This is basically a 2-wheel module that incorporates a drive-train mechanism, a steering mechanism, and suspension. This clever and compact design is due to S. Ariel, who provides complete building instructions for this module. I used two of these modules to build a 4-wheel drive vehicle, with 4-wheel steering and a front suspension. It actually also has a suspension for the rear wheels as well, but the overall suspension was too soft so the vehicle wobbled, so I locked the rear suspension. Perhaps it would have worked better with 8 rather than 4 shock absorbers.

The vehicle is powered by two Power-Functions motors. It moves quite slowly, since the drive train uses a worm gear to rotate the differentials. But it is sturdy and strong. I was able to mount a NXT with batteries in front, along with a sound sensor and a grabber arm (with a NXT motor), and it still moved well.

I built the overall structure from several modules that snap together in about 3 minutes.

Check out the video to see how the vehicle moves, how its suspension allows it to overcome obstacles, and how the modules are put together quickly.

A Power-Functions Remote-Controlled Vehicle

I uploaded a video (with some stills in it) of a Power-Functions remote controlled car. It uses a dual-differential drive so that it can go straight well. (The video also shows stills of an earlier version that used a more conventional steering; but it was almost impossible to make it go straight.)

The Power-Functions parts are from the Monster Dino, which is a great fun to build but not so exciting to play with, since it moves fairly slowly and since you can’t steer it. The same is true for the alternate model, an alligator.

So I was trying to use the remote-control capability to build a vehicle that would be fast and maneuverable. The video shows the result, which is really fun to play with.

Not really NXT, but still fun!

Another ball caster

A long time ago, I published building instructions for a ball caster design by Brian Davis (get it here). Now, mindstormsmaster1 made these nice-looking (LDD) building instructions for a similar ball caster, with a few less beams.

Ball Caster

Here’re building instructions for a simple ball caster, designed by Brian Davis.

Ball Gun from Dicke Bertha Typ II

Matthias Paul Scholz published building instructions for the ball gun of Dicke Bertha Typ II

Clamp-N-lift

Paul made this model which clamp and lift the ball with one motor. It might not be the only possibility, but it is a nice one! Thanks for the LDD instructions, Paul!

Closeable Shovel

Matthias Paul Scholz’s building instructions for the Closeable shovel

Differential Transmission

A differential drive assembly contributed by Bryan Bonahoom (with credit also to Steve Hassenplug for the differential idea). This assembly is a working differential from a single NXT set parts.

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ISOGAWA Yoshihito’s “LEGO Technic Tora no Maki”

ISOGAWA Yoshihito, who has already written  one NXT book and one Technic/Mindstorms book (both in Japanese), has released a beautiful LEGO Technic book in PDF format. The book is available for download; you are asked to pay $10 if you decide to use the book. The book shows a wide range of Technic mechanisms and small constructions. The mechanisms range from simple gear reductions to suspensions, clutches, and much more. The creations include many different vehicles and walkers, all fairly simple to reproduce. The book uses many different LEGO parts, some new (NXT motors, Power Functions motors and battery boxes) and some old (RCX motors, small pneumatic cylinders, the solar cell). In some cases, the book shows how to build essentially the same construction with two different kinds of motors or other specialized parts. The book covers basically all the kinds of mechanisms that you can build with Technic: gears, chains, pulleys, pneumatic, and so on. There is essentially no text, just pictures to illustrate principles and mechanisms. The graphics are beautiful, with clever icons to indicate chapters.

Browsing through the book will surely remind you why you enjoy LEGO so much!

Motor with 90 degrees redirection

Matthias Paul Scholz’s building instructions for a robust framework that redirects the rotation axis by 90 degrees.

NXT Light Barrier

Philippe Hurbain’s (Philo) website has been updated with a cool little light barrier project.

Following this discussion on Lugnet, I built this proof of concept of a light barrier using NXT light sensor and an optic fiber. Any small object passing between the end of the fiber and light sensor phototransistor can be easily detected, even if they have different color or reflectivity.

Scanner designs

Our forums user Spirou published on his website two nice scanner designs - vertical scanner and horizontal scanner. Both designs allow rotating the US sensor around without moving the whole NXT bot.

Small Rotation -> Linear Technic tip

Here is what I believe to be the smallest set of NXT-set parts that converts rotation to linear motion. Turning the blue axle jointer moves the yellow 1/2 bush along the worm gear, pushing the axle and the bent beam on it. Due to the properties of the worm gear, this is one-directional - pushing on the beam does not rotate the worm gear or move the beam itself.