Digital Body

WSJ Article on the Arduino

2009-11-28T12:36:00.001-08:00

The Wall Street Journal posted an article on our friend, the Arduino. Pretty cool!

Some Random Tutorials

2009-11-13T07:07:00.000-08:00

I just found that a class at Carnegie Mellon this fall that is devoted to this topic and they have posted lots of tutorials and hints on their blog that might be helpful. (Note: they are using WordPress to make their blog! Copycats :-)).

As you are using and finding tutorials, make a note of what is NOT out there. For our tutorial I would like your team to provide something that will help the next group trying to make a digital body part.

Safe Arduino 120 volt Switch Control

2009-11-13T06:57:00.000-08:00

A lot of teams are wanting to control 120 volt power with an Arduino. One way to do this is with a Relay, or more specifically a Solid-State-Relay (SSR), but since it requires wiring and high voltage it should only be attempted by experienced electrically inclined people.

I have found a mechanical and safe Arduino tutorial that uses a servo to turn on and off a light switch. I think this could easily be adapted to turning on and off a Power Strip as well, which would allow you to plug anything into the strip and have it turn on and off.

This is the technique I would recommend to use for anything that requires 120 volts. A SSR would be safe to try for a 12volt battery and there are many tutorials around for that, you do have to find the specs for which SSR to buy for which battery.

Conductive Thread

2009-11-12T22:11:00.000-08:00

Here is a video that shows how to sew LED lights into an Arduino using Conductive Thread. They also sell the thread on that site, and probably many others.

The Arduino that is being demonstrated is called a Lily Pad, it's a bit smaller than ours but the software is the same and all of the in/out ports work identically, just a different design.

Floating Lab Collective

2009-11-10T20:23:00.000-08:00

THought you all might be interested in Scream at the Economy, which was put on by a group I am loosely connected to.

Resources

2009-10-20T19:09:00.000-07:00

Processing - The Processing Programming language
Arduino - the Arduino site
Instructables if you have questions about electricity and Arduinos or how to do things.

Sensor Check out

2009-10-20T19:06:00.000-07:00

Sound/Motion - Sam/Alex - Need a Motion Sensor
Brainiacs - Joseph - Need a Motion Sensor
Bits and Pieces - Need a Motion sensor, Has 1 Pressure sensor, need an accelerometer and proximity sensor
Body Group, Asterisk, web cam, could use a Motion Sensor
Air Supply group - using a web cam

eCloud

2009-10-07T21:26:00.000-07:00

Dan Goods is an artist using light reactive glass for a cloud in San Jose Airport.

He's also using Processing to visualize the piece, much like I did for the BMW kinetic sculpture. Always a good idea to prototype and visualize before committing to the real thing.

Prototyping

2009-09-26T13:41:00.000-07:00

The Arduino is actually used a lot in prototyping because it is easy to program and you can continue to rework your program as needed. When we are wiring up our motors and sensors, we will be using breadboards to layout out wires. Essentially when we are doing that, we are starting to design a circuit board, how the wires connect and how the electricity is routed to different things using diodes and resistors as needed. Once you are happy with how it works, it could be made into a real circuit.

But, before we create our working model, you can also use 3D programs to prototype what you want the final product to look like and how it works. I was thinking about the BMW example, and decided to see if I knew what I was talking about when I was guessing how it worked. So, I went ahead and created a 3D animation to prototype this out.

I was curious how many balls would be need to look good, and wanted to see how to generate a video image that could be used to drive the balls vertically as I described. Three-D programs can render lots of channels, and in particular a depth channel would enable me to recreate what I thought they did for the BMW installation. Below is my final rendering:

This is a good proof of concept for making something like this. I now know exactly what it will look like if I have a grid of 80 X 50 balls and I also can experiment with the movie that drives the images. Below is the depth channel rendering that is driving this animation.

All that is needed at this point is to get 450 servos and have each servo be directed by the pixels in a 3D depth channel rendering. It would not be too hard to write a program in Processing that could do what I did in 3D, so really the next step is just figuring out an efficient way to wire the servos, how many arduinos, etc.

Programming and Installations

2009-09-24T08:38:00.000-07:00

Many artists, like myself, have spent our careers avoiding doing anything useful or productive. I mainly try to have fun and make beautiful things. But, as these things go people can usually find a use for what we do and below are some practical examples of how interactive design can be used productively.

The first example is a video display created for Saturn. Look at the video to see it in action.

They used something called "Frame Differencing" to detect areas of motion. By checking each pixel in the current frame against the past frame, the program looks for changes. No change gives us a black pixel, any change gives us a white pixel. That effectively creates a white blob where people are walking and we can use that blob to distort the grass. It is very similar technically to my "hypocenter" piece, where I had an object hooked up to move in relation to how close people were to my birds.

A second example is an installation at the BMW museum in Munich. Here's a video of it in action. Again, not complex in how it's done, but implementing that many stepper motors and keeping them working smoothly was probably quite a challenge.

A Stepper Motor allows us to control how many steps of rotation a motor moves, so for the BMW piece it would allow for precise positioning vertically of the balls. Using an Arduino, we can write a program that translates values into the number of steps to move. For example, if we have an 8-bit greyscale image, a pixel has 256 steps from black to white. Each pixel value could be translated to a stepper motor which might also have 256 steps. If a pixel is white, the motor is set to 256. If it is black, the motor is set to 0.

In this way, we could take an image that is 100 pixels square and reproduce it using an array of stepper motors. That's 1000 motors however, so a bit of work! Since we can do this with an image, it's also possible to do with a video creating an animated sculpture.

We will have a stepper motor as part of our kit, but it is probably going to be pretty small. A sculpture student asked me about this and if you are really interested in Arduino's and stepper motors, you might want to consider the Stepper Motor Shield from Adafruit.com (some assembly required). It is more robust than what we will have and combined with an Arduino could be quite fun to use.

One last note, try a search for "Arduino POV" (Persistence of Vision) on Instructables.com to get some ideas of how a few LED's can be used to dramatic effect when timed to a motor.

The First Post

2009-09-22T21:57:00.000-07:00

Well, someone had to be the first. Here's the info Bryan sent out about the sensors and other useful information:

Every team should have the ARDX Kit, which will comes with various servos, knobs and motors. This page describes how to work each item in the kit and has a section on using relays to power a larger motor:

http://www.instructables.com/id/Arduino-Expermentation-Kit-How-to-get-Started-wi/

In addition, the sensors will be various quantities of:

Force-Sensitive Resistor (FSR)
PIR (motion) sensor
Infrared Proximity Sensor Long Range - Sharp GP2Y0A02YK0F
Accelerometer Breakout Board - ADXL321 +/-18g

In general, it is not that easy to hook up more than one incoming sensor so students should be thinking of a single Arduino input sensor and how that sensor might be used to creative effect. On the output side, it is easy to have multiple outputs, so they should keep that in mind - single source input, multiple outputs. Not saying it's impossible, but creative thinking goes a long way when dealing with these kinds of installations, so they should not go crazy on what is coming into the computers USB port via the Arduino.

In addition to the sensors, you can use incoming data from computers such as a Web Cam, a microphone, incoming feeds from web services like Twitter.com, Google or Facebook. These can be used simultaneously with the Arduino and sensors.

Artists that are using technology in an interesting are below. Of interest to design students, Tony Oursler has one foot in the commercial world as well as the fine arts. He does video work for concerts for acts such as U2 and the like. He enjoys both and doesn't really differentiate.

Ira Sherman www.shermansculpture.com
Chris Burden
Gary Hill
Tony Oursler
Tim Hawkinson
Jean Tinguley
Stellarc
Krzysztof Wodiczko