What do we want in a bicycle? It should be able to be constructed at home, even if your home is a New York apartment. It should be Open Source so our friends can make their own. It should be compact so it won’t clutter up our little apartments. It should be unique instead of another me-too. [Alex Bell], of Bellcycles, is showing off his bicycle on hackaday.io and it fills all the requirements.
The unusual shape drastically reduces the size, turning radius, and storage footprint from a traditional bicycle. It shares the large front wheel design of the penny farthing. Unlike the giant wheeled penny-farthing, the rider is much closer to the ground so it doesn’t require a special technique to get on. In fact, dismounting the cycle is as easy as standing up since there is nothing in front of the rider which is great news for urban commuting.
When my elder brother and I were kids back in the late 1970’s, our hacker Dad showed us this 1960-61 catalog of the Atlas Lighting Co (later Thorn Lighting) with an interesting graphic design on the cover. He told us to do a thought experiment, asking us to figure out how it would be possible to have a machine that would draw the design on that catalog cover.
Incorrectly, our first thought was that the design was created with a Spirograph. A spirograph has two main parts: a large ring with gear teeth on the inside and outside circumferences and a set of smaller, toothed wheels with holes in them for inserting a drawing instrument — usually a ball point pen. You hold the big ring, insert the pen in the smaller wheel, and then mesh and rotate the smaller wheel around the big ring. But spirographs can’t be used to draw irregular, asymmetrical figures. You could always recreate a design. Because of the nature of gears, none of them were unique, one off, designs.
A spirograph set like this cannot make the image above [Image credit: Multicherry CC-BY-SA 3.0]We figured adding some lever arms, and additional geared wheels (compound gears) could achieve the desired result. It turns out that such a machine is called a Cycloid Drawing Machine. But even with this kind of machine, it was possible to replicate a design as often as required. You would fix the gears and levers and draw a design. If the settings are not disturbed, you can make another copy. Here’s a video of a motorized version of the cycloid machine.
The eventual answer for making such designs was to use a contraption called as the harmonograph. The harmonograph is unique in the sense that while you can make similar looking designs, it would be practically impossible to exactly replicate them — no two will be exactly the same. This thought experiment eventually led to my brother building his own harmonograph. This was way back when the only internet we had was the Library, which was all the way across town and not convenient to pop in on a whim and fancy. This limited our access to information about the device, but eventually, after a couple of months, the project was complete.
![A spirograph set like this cannot make the image above[Image credit: Multicherry CC-BY-SA 3.0]](https://hackaday.com/wp-content/uploads/2017/02/spirograph_set_uk_palitoy_early_1980s_perspective_fixed.jpg)
