Working with cams and different types of cam followers

My 16 article on automaton-making for Cabaret Mechanical Theatre is now live on their web site. In this installment, I discuss different sorts of cam followers and how they can be used. The cam gets a lot of attention, but is almost without value in the absence of a cam follower. Read on to learn about the basic types, their advantages, and disadvantages.

Here is where you can read my article on Cam Followers for Automata.

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Gear generator tool allows you to design full gear trains and see them in action!

This new online Gear Generator tool can be used to simulate sets of spur gears. You can plug in all kinds of a parameters, and then animate the gears at various speed to demonstrate working mechanism. You can also download the final results in SVG format. The tool allows you compose full gear layouts with connected gears to design multiple gears system with control of the input/output ratio and rotation speed. The gears are of the involute type which is what most of the world wants -- except perhaps for the clockmakers. This tool is fantastically useful and very well designed too!

Here is where you can check out and use the free online Gear Generator tool.

To learn more about gear design, check out these great reference books such as Dudley's Handbook of Practical Gear Design and Manufacture, which provides comprehensive information on the design and manufacture of gears for the expert and novice alike. Topics include: Gear Types and Nomenclature, Gear Tooth Design, Gear Reactions and Mountings, Gear Vibration, and The Evolution of the Gear Art.

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littleBits electronics kits -- an opensource library of electronic modules that snap together magnets!

Amazon has been creating lists of recommended toys for the holidays for years. I just discovered that they now have a specific STEM Holiday Toy Guide -- that's Science, Technology, Engineering, and Math. This list is big!


Shown above is the littleBits Electronics Deluxe Kit. This is the biggest of the littleBits electronics kits -- an opensource library of electronic modules that snap together with tiny magnets for prototyping. No soldering required. Now that's a great idea! This particular kit features 18 modules. You will have everything you need to make something that blinks, moves, makes noise, and more! these are really clever kits and the have many different ones.

While this kit is the biggest, they offer many more exciting and educational kits. They are something like the SnapCircuit kits which have been available for a while, which also don't require any soldering. Check out the full full line littlebits and SnapCircuits kits. You can have completed electronic circuits humming away on the kitchen table before the plates have been cleared!

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Blast from the past: aging an authentic wood catapult kit, part 2

This is the second in a two part series reviewing the working wood catapult model made by Pathfinders. In the the first part, I reviewed the the kit and gave you some assembly tips. In this part, I'll tell you how I went about making the catapult look like it truly belongs on a medieval battlefield.


What is the Kit and Where Do You Get It?
The catapult kit is sold various places, but can easily be found from Amazon as the Pathfinders Medieval Catapult Wooden Kit.

Getting Ready to Get Old
Once the kit is assembled, you should have a bit of fun testing it out. I recommend throwing small grapes at a pyramid of empty aluminum cans. If you would like to make your catapult look old, read on. For this process, I used the following tools and materials:

* Carving knife
* Small wire brush
* Furniture finish touch-up markers
* Coarse twine
* Elmer's glue
* Sandpaper - 100 grit
* Minwax wood stain - Early American
* Round wooden disks
* Wooden wheel pegs
* Popsicle type "craft" sticks
* Soldering iron with wood-burning tip
* Gun bluing
* Portable hand drill
* Ball-peen hammer

None of these things are essential. You should feel free to use whatever tools and materials you have on hand or can obtain easily.

Making the Catapult's Wood Beams Look Old
The first thing I did was removed the string and washers from the model.

I used a carving knife to take the corners off of the straight edges of the wood. I didn't remove a lot of material because I didn't want to compromise the strength of the wood.

I just shaved off small, irregular shavings to make it look a little less perfect and perhaps as if the beams had been hand-hewn. I also rounded the spoon-shaped end of the throwing arm.

Next, I added the wood knots to the beams. I have a set of three wood finish touch up markers. I used the second darkest color. By gently resting the very tip of the marker on the unfinished wood, pigment from the marker is drawn into the wood fibers in a way that looks something like a real wood knot. Use the underside of the model to perfect your technique.

The knots may look a little too dark at this point, but don't worry. After placing knots of various sizes on the beams, I gave the entire model a coat of Minwax wood stain. I used "Early American" simply because I had some around. You can use whatever color you like, so long as it is considerably lighter than the knots you have made with the marker. This allows the knots to show through the stain. At this point, you should give your catapult some time to dry.

Later, I used a wire brush to give the catapult some scratches and wear marks to make it look like it had been used for years. I also used a wood-burning tool to add some grain lines and cracks to some of the beams. Make sure these lines follow the grain of the wood so that they appear natural.

I dipped the the string that comes with the kit in the Minwax and wiped the excess off with a rag. This makes the "rope" look old too.

Adding the Twine to the Crossbar and Throwing Arm
I am not sure if it is authentic or not, but I thought some cordage wrapped around the throwing arm and crossbar would look good. I also figured this would provide a bit of cushioning. I used a coarse three strand twine for this. I unraveled the strands so that I had a single strand. I tied one end of twine around the crossbar.

Next, I spread some Elmer's glue on the section where the twine was to be placed. I then wrapped the twine in a tight coil around the crossbar. I tied off the end and put a drop of glue on it to keep if from coming off.

This process was repeated on the throwing arm where it meets with the crossbar.

Making the Wooden Wheels for Your Siege Engine
I purchased a set of round hardwood discs that are 2 - 3/4 inches in diameter. I also purchased some wooden toy axle pegs and some craft sticks -- really they are just Popsicle sticks. All three items can be found at craft stores.

I used a soldering iron with a flat wood burning tip to create parallel lines on the wheels to make it seem as if they were constructed from individual planks. I also burned the edges of the wheels a bit to simulate wear and wood grain.

Next, I glued two short lengths of Popsicle sticks to the outside of each wheel to model the boards that would hold the wheels together.

I drilled a 1/4 inch hole in the center of each wheel and in the four corners of the catapult base. I sanded flat sides on the axle pegs and darkened them with marker.

Using the toy axle pegs, I mounted each wheel to the catapult. I glued only the holes into which the pegs go, so the wheels can move freely. Finally, I gave the wheels a coat of wood stain.

Finishing Touches to The Antiqued Catapult
The catapult was starting to look pretty old at this point, but the bright metal washers on the outside ruined the effect. I used the rounded end of a ball-peen hammer to dent one face of each washer. I then rubbed some gun bluing on the surface to give it a dark, oxidized look. DO NOT get this stuff on your tools.

In the end, I spent 30 to 40 minutes making the basic functioning catapult kit, and 4+ hours making it look old! I had a lot of fun doing it.

Where to Get the Kit and Other Supplies
Most of what you need can be found at your local hardware store, craft store, or hobby shop. If you have any difficulty finding these items locally, here are some online sources:

* Pathfinders Medieval Catapult Wooden Kit
* Wood carving knife
* STEEL SCRATCH BRUSH
* Sharpie Touch up Markers - 3 pack
* Sisal Twine
* Elmer's Glue-All
* 100 Grit Sanding Sheets
* Minwax Wood Finish - Early American
* Wood toy wheels
* Wood toy wheel axle pegs
* Cuisipro Frozen Pop Sticks
* Woodburning and soldering tool set
* Perma Blue, liquid gun blue kit
* Cordless drill
* Ball peen hammer

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One toy construction set to rule them all -- Engino 50 Model Engineering Set

The Engino building system features these really cool multi-faceted rods that allow connections on up to 6 sides simultaneously. The rods permit both dense and open construction techniques allowing you to build simple or complex models quickly with a smaller number of different components.

With the Engino 50 Models Engineering Set you can create impressive structures such as a tower, a suspension bridge, and a truss bridge. It also has plans for making a motorized Ferris wheel, a carousel, and a windmill. A few of the other models include a functional weight-scales, a jet plane, a helicopter, and a bi-plane. Printed instructions are included for 12 models and more can be downloaded from the Engino's website.

The set includes the engino 3 volt geared motor to power up either the featured models or your own creations.

Here is where you can get the Engino 50 Models Engineering Set.

Be sure to check out the full line Engino mechanical toys too!

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Book on the 'Theory of Machines and Mechanisms' for the serious student

Time to take your engineering knowledge up a notch? Check out this book I discovered on Amazon the other day. For the non-professional engineer it may be a little weighty, but boy...it's all there! (This fourth edition is aimed at senior undergraduate or graduate students in mechanical engineering.)

Theory of Machines and Mechanisms covers the study of displacements, velocities, accelerations, and static and dynamic forces required for the proper design of mechanical linkages, cams, and geared systems. The authors present the background, notation, and nomenclature essential for students to understand the various independent technical approaches that exist in the field of mechanisms, kinematics, and dynamics.

The book includes a CD with working model animations of many figures from the text to help students visualize and comprehend their movement. A companion website for instructors provides additional information and resources, including PowerPoint-based slides of figures from the text.

Here is where you can get Theory of Machines and Mechanisms

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The world's biggest cuckoo clock in Triberg, Germany

The World Biggest Cuckoo Clock is located in its own house in Triberg, Germany. The construction of the clock was based on 100 year old cuckoo clock, but at a scale of 60 to 1! The cuckoo bird itself measures nearly 14 feet long, and weights an incredible 330 pounds.

Here is a short presentation about the clock and its construction presented by an animatronic clock-seller:

Here is a video of the cuckoo emerging. Clearly the bird isn't entirely traditional and possesses its own animatronic components. As grand as this is, I would have preferred a simple, traditional cuckoo bird.

Here is where you can learn more about the world's biggest cuckoo clock.

[ Thanks Falk! ]

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Insect's legs turn out to be the first mechanical gears found in a living creature AND similar to those on Rock 'Em Sock 'Em Robots

Popular Mechanics featured a story online yesterday that announced that U.K. scientists discovered the first biological gears on a living creature. The creature is a tiny insect is known as the issus, which lives on European climbing ivy and has an incredible ability to jump. As it turns out, the gear-like structures located at a joint on the insect's hind legs aid in that ability to jump. To jump quickly and powerfully, the issus relies on mechanics. The gears are thought to simplify the neuro-muscular feedback system that can slow down an attempt to move quickly. Because the gears are so well suited to transfer power properly, the insect's nervous system simply fires the signal to jump and doesn't need to bother with feedback. It shaves crucial milliseconds off what is often a life-or-death maneuver.

Now for MY discovery. I read the article with fascination. At the end, I realized the gears found on the insect's legs seemed familiar to me. I searched my brain and remembered where I had seen this arrangement before: the classic Rock 'Em Sock 'Em Robot Game! First, let's take a closer look at the insect's joint. As you can see in the animation, the two segmented gears meet at the junction of two body parts where one must rotate around the other. The gears engage to transfer a what I am guessing is a short linear force into a longer, faster rotational force.

Now take a look at the arm joint of this Rock 'Em Sock 'Em Robot. The elbow joint employs a series of gears to convert a short downward motion on the back of the robot into a quick jabbing motion. The assembly is a bit more complicated than the insect for it uses three gears rather than two. On the robot, there is a gear fused to the body at the shoulder. This gear meshes with a second one located on the inside of the robot's upper arm. This idler gear transfers motion to the final gear located at the end of the robot's lower arm. When the lever behind the robot is depressed, the upper arm is raised, causing it to rotate around the shoulder. This causes the intermediate gear to spin a bit. The advancing teeth engage with the ones on the lower arm, causing it to straighten.

My discovery may not be as ground-breaking as that of the U.K. researchers, but I will still gladly accept an honorary doctorate in engineering from any accredited college or university. Please use my contact form if you can bestow these laurels upon me. I would love to be referred to as 'Dr. North'.

If you want to learn more about biomechanics, check out these books on biomechanics.

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Intel creates kinetic art robotic music system inspired by an animated video

A couple of years ago, a video made the rounds on the internet. (Strangely, I don't think it appeared here on The Automata Blog.) It was a 3D animation of an intricate musical system in which bouncing balls triggered notes on an assemblage of musical devices. It was pretty convincing. I think there was a bit of confusion in some circles as to whether the machine was a real thing or not. It wasn't, but now it is. The folks at Intel have used that video as inspiration to create a machine that does more or less what the one in the video did! That's what you see above.

For reference, here is the original video titled Pipe Dream:

Here is where you can learn more about the embedded Intel technology for industrial automation that was used for this project.

[ Thanks Christoph! ]

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The automatic creation of automata: the computational design of mechanical characters

This could be a game-changer in the world of automaton-making. I don't think I've ever had the chance to say something like that.

I caught wind of this project some months ago, but the recent news of this incredible video comes to us by way of Falk Keuten at the excellent blog Spiel und Kunst mit Mechanik. This computer program created by a team at Disney Research, Zurich accepts a desired input motion and then generates the necessary gears and linkages to realize that motion.

From the research paper abstract:

Given an articulated character as input, the user iteratively creates an animation by sketching motion curves indicating how different parts of the character should move. For each motion curve, our framework creates an optimized mechanism that reproduces it as closely as possible. The resulting mechanisms are attached to the character and then connected to each other using gear trains, which are created in a semi-automated fashion. The mechanical assemblies generated with our system can be driven with a single input driver, such as hand-operated crank or an electric motor, and they can be fabricated using rapid prototyping devices.

And it's not all theory or computer simulations, either! The team demonstrated the versatility of the system by creating a bunch of mechanical characters, several of which were manufactured using 3D printing technology. The results are amazing, some showing subtleties of motion that are very difficult to design, but incredibly valuable to the final effect.

Here is the Disney project web site. Here is a link to the research paper (PDF) titled Computational Design of Mechanical Characters.

[ Thanks to John, Falk, and Fred ]

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Ingenious Gadgets book challenges you to guess the purpose of 100 obscure contraptions from the past

Over the course of 224 pages, author Maurice Collins challenges the reader to guess the purpose of 100 mysterious gadgets from the past. A brief description on page accompanies a large color photograph of the strange, silly, and clever contraptions on the adjoining page. Chapters cover gadgets for:

• The Working Day
• Domestic Economy
• The Stuff of Life
• Out and About
• Body and Soul

From the book description:

Marvel at the ingenuity of the cuff holder which, as legend has it, was used by cardsharps at the poker table to hide the ace up their sleeves; find out how to make the perfect camping cuppa 1920s style; and decide whether the 1920s electric comb really could prevent hair loss. If you thought that phone cameras were a great invention find out more about the watch camera of the 1900s; if you've always found shaving too taxing, there is an automatic shaving cream filler and brush in the collection which allowed you to save time in that early morning rush to work - who knows why this never took off?

One of my favorite weekend pastimes is hunting around antique stores searching for old tools and other items. Trying to figure out the purpose of mysterious items is also a big part of the fun. It's interesting to see the huge number of ideas that have been brought to market over the years, as well as which ones never really took off. This book is like wandering through one of those antique stores, but you can do it from the comfort of your living room or nearest coffee shop. This book makes a nice gift for the gadget lover and history buff.

Here is where you can get Ingenious Gadgets: Guess the Obscure Purpose of Over 100 Eccentric Contraptions

Here is Maurice Collins's associated web site: Victorian Gadgets.com

[ Thanks Falk! ]

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Man builds working bicycle almost entirely out of cardboard

We've seen time and again here on The Automata Blog that amazing mechanical things can be made out of unexpected materials such as paper and cardboard. Building a small mechanism that doesn't have to support much weight is one thing, but you can't build anything out of cardboard that takes a lot of weight or shock. Can you? This excellent film by Giora Kariv shows that you can. Follow along as Isreali inventor Izhar Gafni pursues his solitary quest to build a working bicycle from cardboard. He was inspired by a story he had heard about a working canoe made of the same material.

The literature on how to work with cardboard in this way was, shall we say... lacking, forcing Gafni to experiment with different fabrication techniques to see what the material could do. The secret to the strength of the material lies in folding the cardboard. With enough folds, the material becomes quite strong. We also see him dip parts in some type of liquid during his experiments. Whatever the liquid is, I'm sure it helps.

In the end, he sums up the creation well:

It's strong, it's durable, it's cheap. What I like about it the best? It's made out of cardboard!

He accomplished this feat after being told by three engineers that it was impossible. Let this be a lesson to all of us: if you have an idea, a passion for it, and a willingness to experiment and work in the face of doubt, you can accomplish things that have never been done before. Now...go invent something.

[ Thanks Bob! ]

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Ingenious Mechanisms for Designers and Inventors, 4 volume book set

The Glory of a Four-Volume Set

A numbered set of four hardcover books in bright orange that all but announce that you are a brilliant inventor. That's what you get with Ingenious Mechanisms for Designers and Inventors. Looks alone may not be enough for most people to buy this set, but when combined with the wealth of information contained within, it was certainly enough for me. I am very happy with my decision. Read on to find out why.

Lots and Lots of Machines

There are a huge assortment of multi-component mechanisms described in great detail in this four-volume set. The books offer multiple solutions for each category of machine. The organization of the material is a little clunky; you will need to browse all four books to find all of the possible solutions for a given mechanical challenge. That's OK: it just means you get to look exceptionally brilliant when someone comes upon you reading all four books at once.

The machines depicted in the books are of an historical nature. This is not a shortcoming, however. Mechanisms of the sort found in these volumes were state-of-the-art at one time. They are a testament to a practical, real-world ingenuity that most of us can't comprehend. These days we would leave the tricky stuff to a computer. The creators of these machines didn't have that option.

Clear Drawings and Heavy Reading

The drawings in the book are very good -- clear and well labeled line art reminiscent of patent drawings. Here's a sample of what you can expect:

Be prepared to spend some time with these books; they require some careful reading of several pages to understand how a given device works. It's not exactly a quick reference, but it is comprehensive.

Uses beyond Vanity: Education and Inspiration

I have not used much from these books directly in any of my automata projects. For automata makers, the more complex systems may seem like a lot to digest. Nevertheless, there are hundreds of mechanical elements that certainly could be used in an automaton or kinetic sculpture. I can say that these books have greatly improved my understanding of complex machines and they have served as inspiration on more than one occasion.

Let's Talk about the Price. Worth it?

The first glance, the price might set you off. Bear in mind that each of the four volumes weighs in at 500 pages or more. That's 2000 pages of detailed information on mechanical devices! The last time I checked (August, 2012) the set was selling for $108 (at 25% off). That comes out a little over $0.05 per page! Compared to less expensive books on mechanisms and devices, this set is actually quite a good deal -- especially if you factor in the free shipping of four heavy books.

While probably not the first book on mechanical devices you should buy, it is a set than any serious student of the subject should have. Here is where you can learn more and order you own set of Ingenious Mechanisms for Designers and Inventors

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