I've tried building a few of these, and it's OK if you know what you're doing. (Plan to fry a few chips is you're a n00b.) Almost all chips don't have a bootloader yet, so you need to deal with that. For most of the stripped-down models, you also need a USB/Serial converter to load your bits.
Debugging shoddy solder jobs is a pain (I'm terrible at anything surface-mount), so I usually just use an Diecimila for prototyping and deal with custom stripped-down boards later. The chips straight-up are something like $4, so if you're doing volume later on it's worth building your own. The Diecimila has some nice built-in features, like a reset button, onboard LEDs for testing, 12V power jack, female headers for jumper wires, etc.
It's worth keeping a few of them around for rainy Saturdays. "Hey! I wonder if I can make my coffee pot a web server? Can it tweet when the brew is done? Hm..."
At one startup we had a similar setup but using perl and a serial-controlled power switch.
It began with a stoplight but in december we brought in an xmas tree and put on strings of green, yellow, and flashing red lights. For a while "the tree is green" was pleasingly literal.
Here are a few clones:
http://sanguino.cc/
http://www.ladyada.net/make/boarduino/
http://www.moderndevice.com/
http://store.fundamentallogic.com/ecom/index.php?main_page=p...
http://www.eauduino.org/
http://news.jeelabs.org/docs/jn4.html
http://dorkbotpdx.org/wiki/dorkboard (with Serial<->USB http://dorkbotpdx.org/wiki/benito)
And more kickass 'duinos:
http://www.arduino.cc/en/Main/ArduinoBoardLilyPad
http://www.seeedstudio.com/depot/blackwidow-10-p-613.html?cP...
I've tried building a few of these, and it's OK if you know what you're doing. (Plan to fry a few chips is you're a n00b.) Almost all chips don't have a bootloader yet, so you need to deal with that. For most of the stripped-down models, you also need a USB/Serial converter to load your bits.
Debugging shoddy solder jobs is a pain (I'm terrible at anything surface-mount), so I usually just use an Diecimila for prototyping and deal with custom stripped-down boards later. The chips straight-up are something like $4, so if you're doing volume later on it's worth building your own. The Diecimila has some nice built-in features, like a reset button, onboard LEDs for testing, 12V power jack, female headers for jumper wires, etc.
It's worth keeping a few of them around for rainy Saturdays. "Hey! I wonder if I can make my coffee pot a web server? Can it tweet when the brew is done? Hm..."