As a grad student in architecture, I am lucky to have ready access to all of the basic tools needed to make technical drafts. I did some planning drawings of the mechanisms I’m going to build for the distance interaction machine.
In case you don’t know what I’m referring to, you may want to skip down to the final section of my last blog entry where I present the idea. In short, I’m going to make a distance interaction system where both users (one in each remote location) have a set of tabletop mechanical pieces that can be arranged in different ways to make a sort of improvised kinematic chain. The goal of the builders is to take a simple input force (like a ball coming out of a tube) and translate it to an output (like a ball going into a different tube). The path of the force is supposed to be fun and indirect with lots of detours and bits and bobs on the way. A Rube Goldberg machine, if you’re familiar with the idea.
I’m trying to build this machine in as hardware-store-themed a way as I can, and so consequently I’m trying to use only off-the-shelf parts as much as possible. Below is a drawing of a simple machine I call the Circle Swing that can introduce a fun delay into the action. A mass (a bolt, some washers, and a tightened nut) on the end of a string can be wound up around the rod it’s on. If it’s released, it will swing around in ever increasing circles as it falls, like a tetherball. I designed it with a magnetic base so that it won’t topple easily, since it will be tall and skinny, and I want it to be easily positioned without a big footprint getting in the way.
Drawn at 1/4 scale. Click and hold on the image to see a magnified view
A careful user of the Circle Swing could use the swing, or the mass at the end, as the hitting instrument to pass on its force. So far I haven’t designed any way for the thing to hold its mass up in its sprung state, wrapped up near the top of the device. I’m not sure what form that’ll take so I’m just going to set it aside for the moment and not worry about it. It is the sort of thing I can leave to the user’s creativity.
I drew what I’m calling Domino Rods, which are 1/2” square rods, hinged on a frame made of 1” angle rods. The idea is that you set them up and they’re nearly vertical, but leaning slightly to one side against a little support screw. A light touch sets up the domino effect which can then knock something over at the end. These have a slightly bigger base as I drew them, but maybe I should replace it with a smaller magnetic base like the Circle Swing has.
One advantage of dominoes is that the force can push on them at a low height but then be transmitted out at a higher elevation—in a simple kinematic gravity-based machine height gains are key, since you’re frequently using the loss of height to power every step.
The third design I drew today is Ladder Fall. It expects a ball (1/2” bearing ball is what I’ll probably use) to come in at the top and zig zag its way down until it exits at the bottom. Since the ladder rungs will be made of threaded rod, it should make a nice rhythmic rattle as the ball rolls down the face. Just as in the Circle Swing, I think I’ll probably need to add a mechanism that retains a ball at the top to start with until it gets released, or perhaps also provide an off-ramp of some sort for the ball to leave at the end in a particular direction.
I wanted to do some drawings to give myself a better idea of what I want to make, and it doesn’t hurt that I find manual drafting to be an interesting exercise unto itself!
Next up, I’m going to go to the hardware store and buy a bunch of materials to make stuff out of, including the parts I identified in these drawings. I plan best by making (i.e. not planning at all) and I know that going to the store I’ll find plenty of inspiration for lots more mechanisms to make!