Children on a Seesaw

I decided to try and build another model using my LEGO escapement mechanism, and came up with this model of two kids playing on a seesaw (or a teeter-totter, as it is often called).

There are a couple of differences to note between this model and the model of the cow jumping over the moon.  For example, in this model the seesaw itself acts as the pendulum. I have also introduced a 3 to 1 gear reduction between the escapement gear and the spool letting out the weight. This results in a run time that is 3 times longer than it normally would be (15 minutes for this model), but also requires that the weight be 3 times the mass in order to exert the same forces on the escapement arms. Of course, this could be expanded even more, with further gear reductions or the introduction of pulleys, to produce even longer run times.

I have put together building instructions for the core escapement mechanism, if you would like to see how it is built, or even try to incorporate it in your own models.

Escapement Mechanism Instructions

Building Guide

PDF File

Digital Model Files

LDraw FileLDD File

Additional Resources

Parts List

Rebrickable

Note that the performance depends heavily on how freely the pendulum can swing and the escapement gear can turn. Try your best to align all the Technic components to minimize any friction in the system.

Seesaw Whole

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The Cow Jumped Over the Moon

Over the last few weeks I have been experimenting with building escapement mechanisms out of LEGO pieces. Traditionally, an escapement mechanism is used to power the timekeeping device of a clock, but I wanted to try and use one to power a LEGO model. I decided to build a model of the cow jumping over the moon, from the traditional English nursery rhyme.  Here’s the video of it in action along with an explanation of how it works.

There are actually a lot of ways to build an escapement mechanism using standard Technic gears (and if you search YouTube you will find a lot of videos of them). I wanted to do something a bit different, and try to build the gear itself out of LEGO pieces as well, which you can see in the video and the pictures below.

This model will ‘run’ for about 5 minutes before the weight has to be reset.

The Cow Jumped Over the Moon

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Happy Holidays!

Looks like Santa has been bulking up a bit too much during the off season. If you celebrate Christmas, hopefully this doesn’t happen at your house.

Happy holidays to everyone from Kristal and I!

Christmas 2015

And here’s a full shot of the vignette.

Christmas 2015 Full

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Skating Penguin

This is Kristal’s latest model, a kinetic sculpture of a cute little penguin skating on an iceberg.

It uses a pretty ancient mechanical device, called a Trammel of Archimedes, to achieve the motion. In recent times variations of this mechanism have been sold as toys and novelty items, often labeled as ‘Do Nothing Machines’, but it can actually be used as a drawing device to create perfect ellipse shapes.

I have put together instructions for building the penguin and the Trammel of Archimedes, which you can find below.

Skating Penguin

Penguin Instructions

Building Guide

PDF File

Digital Model Files

LDraw FileLDD File

Additional Resources

Parts List

Rebrickable

Trammel of Archimedes Instructions

Building Guide

PDF File

Digital Model Files

LDraw FileLDD File

Additional Resources

Parts List

Rebrickable

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EV3 Cookie Icing Machine

After returning from my trip to Qatar for the Word Robot Olympiad, I was super psyched to build another LEGO Mindstorms machine. Kristal suggested that we build a cookie icing machine for the upcoming holiday season, and so, we present to you, the EV Icer!

EV Icer

I have put together building instructions for the EV Icer, along with the program file for running it, but be sure to read the operation notes below! The icing results can vary drastically depending on many factors. When everything goes according to plan it actually works quite well. All of the cookies in the picture at the end of the post were iced using the machine. To build the EV Icer you only need the LEGO Mindstorms retail set number 31313.

Instructions

Building Guide

PDF File

Digital Model Files

LDraw File

The motors should be connected to the ports as follows:
Port A – the medium motor for the cookie turntable
Port B – the large motor for the squeeze roller
Port C – the large motor that pushes and pulls the turntable assembly

The most important factor to successfully icing a cookie is the consistency of the icing. If it is too runny you will get a blobby mess. If it is too thick you won’t get a complete design. It’s hard to describe the ideal consistency, but it’s probably about the same as you would want if you were icing the cookies by hand. You may have to experiment to find the right balance. Don’t expect it to work perfectly the first time you try it.

You will probably get icing everywhere, especially if it is too runny. Be sure to adjust the height of the ‘ice stopper’ so that it blocks the end of the icing tip when it’s not icing. For smooth operation of the squeeze roller it is best to fold the sides of the icing bag in on itself as you drape it over the squeeze plate, before securing it in the back.

We are using a Wilton brand decorating tip (#4 Round) with a Wilton brand Coupler, which fits snugly in the bracket I have designed (see picture below). I don’t know if other brands of icing tips/couplers are much different, but if they are you will need to improvise to keep the icing tip secure. We are just using a generic icing bag.

The height of the icing tip should be adjusted (by sliding the entire squeeze roller/plate assembly up or down) so that it is just above the top of the cookie.

The patterns are designed to work with cookies that are 9 LEGO studs in diameter. Any larger and the cookie will get caught up in the frame. If they are much smaller the icing will be placed off the edge of the cookie.

Feel free to delve into the program file to adjust some of the variables. Manually adjusting the power applied to the motors is one way to accommodate icing of different consistencies.

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Sisyphus Kinetic Sculpture

A couple of months ago someone pointed me to this fascinating video from Disney Research – Computational Design of Mechanical Characters. It’s full of some amazing character models featuring realistic motion, all achieved using mechanical links and gears.  Of course I was immediately inspired to build my own version of the Sisyphus model out of LEGO parts. I definitely wanted to add my own touch to it though and, in addition to tweaking the geometry a little, I decided to add a boulder and extend the motion to it as well.

You can see the results in the video below, where I also discuss the details of the mechanics.

I have put together building instructions for both the full model and just the core, if you are only interested in building the main mechanism.

Full Model Instructions

Building Guide

PDF File

Digital Model Files

LDraw File

Additional Resources

Parts List

Rebrickable

Core Model Instructions

Building Guide

PDF File

Digital Model Files

LDraw File

Additional Resources

Parts List

Rebrickable

Depending on the relative orientation of the two crank shafts when you connect the chain, the motion of the legs and the body/boulder may not be in sync. It’s quite easy to adjust this after the fact – just slide the 12 tooth double bevel gear (the black one on the main drive shaft) to disengage the leg crank shaft, orient the two crank shafts as they are depicted in the instructions, then reengage the gear.

Sisyphus

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World Robot Olympiad 2015

I just got back from one of the most amazing LEGO related trips I have ever been on. Along with 14 other LEGO Mindstorms builders, I was in Doha, Qatar for the 2015 World Robot Olympiad finals. We were there as ‘Mindstorms Experts’, to inspire and entertain the attendees with our own LEGO robots. Now, having only ever built two EV3 models, I don’t consider myself anything even remotely close to an expert, but Marc-Andre was still kind enough to invite me along for the ride.

Mindstorms Experts

The venue was enormous, and we were set up in some stalls in the yellow section of the picture below, modeled after a traditional souq (marketplace).

WRO2015 Venue

I didn’t actually get much of a chance to take in the event myself, as we were swamped with people the entire time, but there were over 1000 students in 450 teams from all over the world testing their robots in various competitions. The highlight of the event for me was meeting all of the other builders I was with, most of whom I only knew beforehand through their online presence. I didn’t get a chance to take pictures of all of them with their robots, but here are a few.

WRO Experts

It was definitely the most impressive display of Mindstorms creations I have ever seen in one place. Just check out this list: Michael and Michelle with the Cubestormer 3 and 6-axis Robot Arm; Mark and his parents with ELFi; Marc-Andre’s R2-D2 and 3D Printer; Anika’s Fish Hunting Shark and NXT Lab; Andreas and Henning’s Paper Cube Factory; and too many robots to mention from the legendary Yoshihito and Vassilis (Nextstorm).

As for my own creations, a lot of the kids were pretty excited about trying to beat the black box in real life, and I think Bricasso printed almost 100 mosaics over the course of the three days.

My Table

Aside from the event itself, many of us were there for a couple of extra days, and made as much of them as we could. We had so much fun bashing through dunes, riding camels, sampling Arabic coffee, wandering through Souq Waqif, admiring the architecture, visiting the Museum of Islamic Art and eating like Persian Royalty.

Doha Adventures 1

Doha Adventures 2

If you ever find yourself in that part of the world all of the above are highly recommended.

I’m not sure when I’ll have the opportunity to go on an adventure like this again, but if I do I already can’t wait for it to begin!

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Working Combination Safe

A couple of weeks ago I stumbled upon some videos explaining how combination locks work and immediately headed to my LEGO collection to see if I could build one of my own.  I decided to build a typical 3 number combination lock and incorporate it into a LEGO safe. Check out the video to see exactly how it works. Step by step building instructions can be found below.

Instructions

Building Guide

PDF File

Digital Model Files

LDraw FileLDD File

Additional Resources

Parts List

Rebrickable

Some notes on the construction.

For the ‘numbered’ dial I’m using the printed dish from set 4488 Mini Mellennium Falcon, which was released way back in 2003.  There are a couple of other printed dishes that might work, but none of them are all that readily available. I would recommend just custom decorating a regular dish.

Be sure you actually know the combination before fully assembling and locking the safe! I designed this safe so that you can’t just take it apart normally. If you have to break into it you might have to physically break some pieces.

You can actually change the combination by changing where the ‘tabs’ are located on the discs. Using the axles like I have done only really gives you a few options of where to put them, but you can use other parts to create the tabs as well.

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The Heist

The minifigs are after my gold!  I thought I would have some fun with my latest project, a working LEGO combination safe, and put together this fun little video. I’ll be posting instructions for how to build the safe next week, along with a showcase video explaining how it works. Meanwhile, enjoy the action!

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