Archive for Physical Computing

A game that mixes the interaction of physical and digital objects. It draws influence from games like pinball, pachinko, tetris and wack-a-mole.

The Game: The physical game board has 5 irises staggered at the bottom. The irises will open and close by the use of servos working behind the game board. A processing sketch is projected onto the board with circles in positions corresponding to each iris.

Particles/balls/objects fall from the top. The objective of the game is to catch these objects by opening the irises. To open an iris, the player presses the button on a physical controller, which triggers the servos. Each iris will only stay open for 2 seconds then closes again. If the object hits an open iris, player scores a point (iris lights up/blinks). If it hits a closed iris, it will bounce off and change its vector. At that point, the player still has the chance to catch it by opening one of the irises in the next row. If the object is never caught, it falls off the screen and disappears.

It sounds like a fairly simple game, but because of the timing, it takes quite a bit of skill. Sometimes it is best to catch one in an open iris, but other times it is best to bounce the ball off a closed iris and catch it in an open one.

NOTE: Probably the most popular question I received during the show was “where is the camera?!” The answer: there is no camera! It’s all done in processing using collision detection algorithms! There is really no need for machine vision when I can define the areas of the irises and track positions of objects in Processing.

Design of irises derived from thingiverse http://www.thingiverse.com/thing:31855 adapted for laser cut acrylic.

Arduino & Processing code can be found here!

PDF of all the laser cut parts can be found here!

Team:  Xuedi Chen, Andrew Siegler & Tarana Gupta

For more information, see earlier post on development & construction process.

Iris structure:

I want to ultimately make the moving parts out of plexi but I made a prototype of one iris structure out of wood (because plexi is expensive!) and tried to hook it up to a servo. While the mechanism works by hand, albeit roughly, it does not work so well with the servo because of several reasons. 1. Material has a lot of friction. 2. The tolerances of the track on which it rotates needs to be tightened up a bit to decrease side to side movement. 3. The screws may be adding some extra friction from the threading.

I’ve been wrecking my tired mushy brain for weeks thinking about a fun and interesting project to do for a final project. I became very fascinated with this iris mechanism (pic below), which I first saw a print of at Maker Faire this year. The way it moves is so simple and elegant, so I decided to incorporate it. At first I imagined a field of these reacting to some external stimulus. While it may not be hard to physically build 50 of these, programming them would probably pose a huge problem I’m not sure I’m ready to tackle on my own. So I scaled back…

The Idea So Far…

I’m imagining an infinit game with a physical board and processing projection. The vertical game board will have 10 of these irises staggered at the bottom. The irises will open and close by the use of servos working behind the game board. A processing sketch will be projected onto the board with circles/buttons in positions corresponding to each iris.

Particles/balls/objects will fall from the top. The objective of the game is to catch these objects by opening the irises. To open an iris, the player presses the button in processing, which triggers the servos. Each iris will only stay open for 3 seconds then closes again. If the object hits an open iris, player scores a point (iris lights up/blinks and the button in processing blinks). If it hits a closed iris, it will bounce off and change its vector. At that point, the player still has the chance to catch it by opening one of the irises in the next row. If the object is never caught, it falls off the screen and disappears.

It’s a simple idea right now, not fully developed yet, but sounds like fun.

Another idea I was toying with is working with the Magic Ball. I thought about actuating maybe 3 large ones (made of mylar) with muscle wires and installing LEDs inside them. Maybe it would react to external stimulus or also to a processing projection. The end mood would be like an organism that breathes (by movement of muscle wire and dimming of LEDs) or grows and shrinks depending on how many processing particles is being fed to it. Also, half baked idea so far.