Using simple software and hardware tools, I built a very quick-and-dirty interaction prototype for my bus stop project. (See this previous post to get caught up on the project if you’re unfamiliar.)

Project update: drawing inside of a limited freedom

I have updated some aspects of my fabrication plans for the bus stop machine. Whereas before, I wanted the users to be able to collaborate to draw anything they want (i.e. trace along any path), I was having some trouble figuring out how to build a system that would allow for legible drawing and erasing. I shifted my thinking a bit and decided that it might be more successful to try one of two different tacks:

1. Ferrofluid circus possibility

The idea of this design would be a thin glass-walled container with a bit (maybe ~20cc) of ferrofluid in the bottom, and filled the rest of the way with a lower density oil. Ferrofluid, for the uninitiated, is a black oily fluid with very small iron particles in colloidal suspension. The fluid has beautiful and surprising macro-scale effects when subjected to a magnetic field: the stronger the local field, the higher the fluid’s density in that volume instantly becomes.

In air, the fluid makes these very beautiful symmetrical mountain ranges near a magnet:

ferrofluid in air image from Wikimedia Commons

In museums I’ve seen nice interactive exhibits that submerge (and seal) the fluid in a vessel filled with oil or another inert fluid. Bringing magnets near the container allows for beautiful interactions without having to worry about the ferrofluid making a mess. (Without a waterproof barrier, it’s very easy to get it stuck to a magnet, as you might’ve guessed!)

ferrofluid in liquid image from Concept Zero, who contributed to the pictured exhibit for the Science Museum of Minnesota

For the bus stop piece, I was thinking about building a ferrofluid display case with some simple little fluid circus toys inside the vessel. The two users would collaborate to move a magnet (one user controls the magnet’s horizonal motion and the other controls its vertical motion) to lift ferrofluid from the bottom of the container to drop it into ramps, seesaws, pinwheels, and such. These look like this in little simple oil-and-water desk toys:

oil and water desk toy image from an Ebay product page

However, before prototyping the ferrofluid design idea, I decided while it did allow for, and indeed require, some sort of input from two users at the same time, it’s not fundamentally creative. There aren’t that many degrees of freedom, as the roboticists among us like to say: all you can do is choose where to deposit the ferrofluid, but not really much more. You can’t draw pictures or try to back-engineer the mechanism of the magnetism or do other sorts of exploratory play. So having throught it over, I set aside the idea of a ferrofluid circus in favor of…

2. Mechanical flip-dot display possibility

You’ve seen flip-dot displays in public spaces. They’re often found in transit contexts, like on the front of buses or on big boards announcing departures. Here’s a close-up of a typical flip-dot display:

flip dot closeup image from Wikimedia Commons; this particular display also sports LEDs in the corner of each pixel so it works well day and night

Close up, they’re just a bunch of lined up dots that can mechanically flip over to reveal a black side or a yellow (or white) side. Taken in aggregate they can form an image, language grapheme, or whatever you want.

In this post I go over some of my efforts to build my own analog version of these things. Sneak peek of what a prototype of mine looks like:

magnetic mechnical pixels

What matters for this context is that having settled on these dots as a medium of choice for my bus stop drawing machine, I wanted to better understand how well two people might be able to use these for making drawings together.

Interaction prototyping

Building a purely mechanical system is great—they work even when the power goes out and never need firmware upgrades. But you don’t get it for free: once it’s built, you’re pretty well locked in to whatever design decisions you made.

I had some questions about collaborative drawing with a flip-dot system, the answers to which would inform some aspects of the mechanical model. It’s difficult to build even a low-fidelity mechanical model since there are literally hundreds of moving parts in a flip-dot system. But you know what moving parts are real easy to use? Pixels on a screen!

In the space of a couple hours, the same time it took me to optimize part of the silver pixels pictured above, I was able to write a Processing sketch and wire it up to an Arduino with two knobs to serve as a mechanical input.

The two main questions I wanted to investigate with my prototyping:

  1. How many pixels are needed for an effective shared drawing experience?
  2. What kinds of interactions do people have with an Etch-a-Sketch–type drawing machine when they’re not given any instructions?

I’ve really only begun experimenting. But here’s a taste of what I’ve seen:

Dyani and Nitesh are both architecture students so they’re quite accustomed to creative collaborations. Here they are using the system:

Dyani and Nitesh

And here’s what they were drawing together:

shared drawing

I madly scribbled down some of their banter as they were working together, because I thought it was really instructive at revealing their process and the shape of their collaborative attitude. Some quotes, in chronological order:

— What if we go really fast? — What if you go really slow and I go really fast?

— I’m gonna slide to the left real quick, ready?

— Should we just try to cover the whole thing, I guess?

— Is there a restart?

— I wanna go off the grid!

— Oh it’s a kangaroo! — I’ve lost the kangaroo. — Kangaroo no more. It was a fleeting creature.

— I feel like I could do this for a long time. — Yeah, it’s strangely balming.

— Looks like a lemon. — Yeah, it does. — We drew a lemon! — High five!

a lemon

I would feel great getting strangers to have this sort of conversation together in a public space; they’re truly collaborating, discovering, and problem solving together. They’re engaged in a shared creative process, and one of my favorite parts of the use of the flip-dot large pixels is that shapes sort of reveal themselves, in the same sort of way that they would in clouds and constellations. The kangaroo came out of nowhere and suddenly looked like a kangaroo, and the lemon was what happened when they tried to draw a circle. In this way, it’s a sort of a group-driven Rorshach blot and Ouija board.

More experiments to follow! I will be investigating the results of manipulating the resolution and aspect ratio of the pixel array. Also, since there’s no reason for my mechnical pixels to be lined up in straight rows, I’m also considering trying out a honeycomb arrangement to see if that would have any effect on the drawings or people’s interactions. (The sneakiness of using a honeycomb is that it’s very easy to draw straight horizontal lines, but very difficult to draw vertical ones; perhaps this asymmetry would add an interesting dimension of challenge, or maybe it would just frustrate people.)