Introduction: Strandbeest Inspired 3D Printable Walking Machine
This Instructable will guide you through the process of creating your very own walking machine. The design of this toy was inspired by Theo Jansen's Strandbeest creatures, and combines 3D printing with some standard hardware to put the beauty of Jansen's walking mechanism in your hands.
Step 1: Parts List
In addition to the printed parts, this design utilizes some standard hardware. These include three aluminum rods, 40 pins, and 20 washers, all to add the spring to its step. These 63 parts are easy to find online or at a hardware store. Below are links to the hardware that I used:
1/8" dia. aluminum rod: http://www.mcmaster.com/#9062k24/=x86afe
1/16" x 13/16" spring pins: http://www.mcmaster.com/#98296a037/=x86bz6
0.141" ID steel washers: http://www.mcmaster.com/#92141a007/=xc45cq
The aluminum rods need to be cut to 6 3/4" lengths (or ~171mm, if metric is your thing). Fortunately, aluminum is a forgiving metal and cuts easily with a hacksaw blade or wire cutter.
Step 2: Printing the Parts, Part 1 - the Numbers
This toy requires a lot of parts. Though it may sound daunting at first, the beautiful simplicity of the walking mechanism that this machine employs is reward enough for anyone attempting the build. Read on, brave maker.
One walking machine consists of 107 printed parts and 63 non-printed parts, for a total of 170 individual parts that comprise the machine. Of the printed parts, there are 13 unique shapes that, when assembled, form 61 moving pieces. The rigid skeleton that holds the machine together is composed of 9 elements, while the other 161 parts form the legs and walking mechanism, all driven by the central crankshaft which accounts for 21 of those parts.
The skeleton, assembled crankshaft, and unassembled parts are shown in each picture, respectively.
Step 3: Printing the Parts, Part 2: Prepare the Files
There are 8 print layouts, which each take an average of 2 hours to print. It'll take a few days.
The following print settings are generally comfortable, but play with them as you like to achieve your desired result:
Layer height: 0.20 mm
Step 4: Printing the Parts, Part 3 - Organization Is Key
It's helpful to start putting the parts together while waiting for the rest to finish printing. This helps keep track of your progress and is also a good way to make sure everything fits together snugly.
For optimal use of time, I recommend printing the parts in this order:
2) Ligament 1
4) Thighs (x2)
5) Ligament 2
7) Shins (x2)
Step 5: Assemble the Crankshaft
The crankshaft is what coordinates the movement of all the legs. In order to understand the crankshaft, it is best (though not required) to put it together before assembling the whole machine. This will help later on in the assembly process. The crankshaft consists of 21 printed pieces. These pieces fit together to create the heart of the walking mechanism, which uses five phases in a 120 degree rotating pattern.
I recommend assembling the crankshaft as depicted in the photos, periodically checking that the symmetrical 120 degree phasing is accurate.
Step 6: Assemble Your Walking Machine
Once all your parts are printed, final assembly can begin.
Start by carefully removing the first phase of the crankshaft. This is what you will use to assemble your first pair of legs. Keep the unused portion of the crankshaft intact throughout the assembly process, as this will make it easier to maintain the crucial 120 degree phasing as you add more parts.
Thread on the ligaments and thigh assemblies, taking care that parts are added exactly as depicted in the photos. Don't forget to add the washers as you go! It is very difficult to add them after the fact.
No tools other than the parts themselves are required for this assembly, though I would recommend having some super glue and some oil on hand, to keep any loose pieces from wiggling apart and any tight joints rotating freely. This is by far the best glue and oil combo I've found:
Step 7: Testing and Troubleshooting
The walking machine walks best when applying firm downward pressure to the center of its top bar and pushing it forward and backward. Rigorous exercise will help to work out any kinks over time.
If your machine is not walking properly, check that the crankshaft has been assembled correctly, and that the ligaments are all oriented in the right direction. These machines can be unforgiving of assembly errors, but can be taken apart and fixed if necessary.
Step 8: An Exploration of Filaments
This walking machine prints great in a wide variety of filaments. As with maps, the fewest number of colors that you can use while making sure that no two parts of the same color touch is 4. But if you wanted to print a model in which every single part was a unique material you would need 66 different types (there currently exist about 30 materials available as filament).
Step 9: Epilogue
The beauty of this design is that anyone can find joy in the animal-like movement of the walking mechanism. Unlike others, this particular design has ten legs in total, so when it's walking towards you all you see are five legs across. The odd number of legs breaks up the walking pattern in an interesting way - because the crankshaft has only three phases, and three doesn't divide evenly into five, the pattern of its motion is disguised and rendered even more visually appealing. Its wide, flat faces catch light in different ways, giving it a warm profile, and the weight provided by large, solid pieces make for a durable toy.
This design is very malleable and open to reinterpretations, improvements, and upgrades. Experiment with new materials, see how much it can carry, build it really tiny, or really big! Or hack the design to add motors and make it remote controlled. The possibilities are endless. Have fun, and dream on...