The idea that a person can create a LEGO model, which can then create something entirely new on its own is a very exiting concept. It brings the model to a point where it is a tool; a means of creating more than just itself.
The inspiration for this model came when I saw the wooden Cycloid Drawing Machine by Joe Freedman. Its simplicity of operation and yet its complexity in artwork made me curious whether it could be reproduced in the brick.
The PsyCloid design is different in that it has freestanding boxes that can be moved around the turntable. A slight change in position creates a different design. Further adjustment is possible by placing the drawing arm onto a different pin on either drive motor. Placing it further away from the center creates a much larger pattern up to 20cm in diameter. The variation possible with this setup makes it almost impossible to repeat exactly the same pattern.
It turns out, though, that making a well-functioning system is a lot more complex than I anticipated. Getting the gear ratios correct is a vital step to making the mathematics work; a step that I skipped right over when I started. My first idea was to use the speed dials on two rechargeable battery boxes to drive either end of the arm, and that my changing the speeds, I would be able to obtain the same result as with a gearbox. I eventually rebuilt the second box (under the sliding arm holder) to include Sariel’s 5 speed linear gearbox. This proved to be a better solution as the two drive arms were paired together with the gears, ensuring that they would not go out of sync as with the two motor setup.
The drawings created by the machine were then scanned and edited in Photoshop. First contrast was added (since I used very light green and blue pens), then I inverted the colours. Then I was able to adjust the hue. The change in colours was possible firstly because two different pens were used on the machine, and secondly a very feathered selection was made, and the hues locally changed to the image in post production.
I personally believe that a much smoother, bigger and better machine can be built, and hopefully this project inspires someone to make it.
Here are a few facts about the build:
Control: On/off switch and speed dial on battery box
Drive: 2 XL (later only 1 XL motor was used)
Gearing: 1:16 for the first drive arm. 1:640 for the turntable (this was later geared down to 1:1778.489!)
Second drive arm was initially geared like the first and was then geared using the 5 speed
Batteries: 2 rechargeable battery boxes (later only 1 was used)
Size: Drive boxes: 12×14 studs and 6 bricks high
Drawing arm: 69 studs long
Instructions: Disassembly photos (Bricksafe folder)
High Res Photos and Drawings: (Bricksafe folder)