The goal of this project was to automatically generate a mechanical computer.
Furthermore, it should...
...compute something useful,
...be made to order, and unique to each person,
...and emerge from the 3D printer pre-assembled, ready to run.
Sure, um, no problem.
The first major obstacle: Using 3D modeling tools
Let's put it this way: I can build something in a 3D modeling package, just like I can eat my breakfast using only a hammer. I won't starve, but I sure don't want anyone looking over my shoulder while I'm doing it.
I'm a software engineer, but there's no way I'm comfortable enough in a package like Maya or Blender to build a custom computer made of gears.
...still, the process was ultimately successful (you can play with the 3D model here), so the rest of this instructible will be an outline of what was involved.
(See the attached PDF for an interesting short description of the final machine)
Step 1: Problem 1: What should it compute?
- At the time it's made, you specify the dates of birth (month, day and year) for two people. That's all.
(The machine is built specifically for those two people, and can't be changed.)
- The finished machine will have a calendar display (for 100 years or so), and three pairs of indicator needles.
- ...so when you set it to the current date, the needles will show the Biorhythm (intellectual, emotional and physical)
readings for those two people. So they can know (just for example) when they're in sync physically. Ahem.
I know about biorhythms because when I was in 7th grade my folks helped me print out computer-generated biorhythm charts as gifts for my teachers. Those charts were amazing, because it was 1981 and a lot of really basic computer stuff was amazing in 1981.
In case you haven't heard about biorhythms, I'll do a quick overview, but you can read about them here:
Biorhythms are kind of like astrology. They're interesting and fun, but not actually science.
The idea is that there are 3 cycles which govern how you feel, and they oscillate at different frequencies
23 days for "physical"
28 days for "emotional" (Yeah I know, but I swear I didn't make that one up)
33 days for "intellectual"
As these go up and down, you supposedly get strong/weak, cheerful/cranky, and smart/dumb.
Like I said, it's fun to share with friends or an SO, but not actually science.
Besides the fun, the reason I decided to do this is that the computer only has to produce three sine waves. That's all. If I can't make a computer that does that, then I've got no business making anything more complex, like an orrery or an encryption device.
So whatever other parts there are, the machine is going to need three special gears for sure (see picture): One with 33 teeth, one with 28 teeth, and one with 23 teeth.