Understanding Arduino...?

First off, let me apologize for the elementary nature of this question, but I am trying to wrap my head around this physical computing thing, and it continues eludes me. (I am an artist who’s knowledge of engineering doesn’t extend much further than LED’s and resistors)

My question is this. Lets say I was building a series of sculptures that each had a different lighting function. Would I purchase one Arduino Diecimila board and a number of ATmega168 chips to program and install in each sculpture, or would I need to purchase a separate Diecimilla board for every instance? I did some searching, and couldn’t really discern whether or not the AT chips could operate separate from the programing board. If so, is can I just purchase the chips from say, mouser, or do I need special versions of the chips to integrate with Arduino? (I’m unclear on whether Arduino is simply the programming language used by this chip or a more complex interactive process)

Again, sorry if this should have been obvious, but I, as of yet, havn’t been able to confirm either of the two options…
I appreciate the help!
Matt

It depends on how you want to program them.
The easiest/most expensive solution is to put an Arduino that can be connected via USB into each sculpture. Then you could take your pc from one to the next and download the program written in the Arduino IDE into each board.
The solution you are probably looking for (if I understand you correctly) is to put the chip with the bootloader installed (there are at least two sources for this) into each sculpture. To program them, you write the program in Arduino and download it to a chip on a Diecimilla or NG, then remove that chip and place it into your sculpture (either into a less expensive Arduino or clone that lacks a USB port, or into a board of your own design that interconnects conveniently to your project).
The solution I can’t personally recommend (not being, myself, capable of implementing it) would be to design a custom pcb using the ATMega168 (or another AVR processor) and to program it using C with an ISP programmer and Atmel’s software tools. This might be the most economical, but would require the greater development effort. It would also negate the benefits of this forum! Here you can get good advice on how to implement your ideas in Arduino code.

You do not need a “whole” arduino board in each sculpture, but you do need a little bit more than just the ATmega168 chip. A couple of vendors offer “run time” or “bare” boards that are much lower in cost than a full arduino. These tend to lack “shield compatibility” (they’re a different shape) and USB capability. Some retain programability via special cable. Prices are as low as $2 for bare boards, $10-$20 for “full” kits (which you probably don’t need all of.)
http://www.nkcelectronics.com/arduino.html
http://moderndevice.com/RBBB.shtml
http://www.adafruit.com/index.php?main_page=index&cPath=19

Alternatively you could have one Arduino and run wires. :wink:

Really the bare minimum you can cut a Arduino down to is a AVR chip and a 5v supply.