Just wanted to share a new project I started. It's using the Arduino to control a hydroponics setup I made. There are pictures here: http://www.flickr.com/photos/nemik/sets/72157622608195083/
The Arduino sketch was initially just very simple to control a pump for a few seconds every 10 minutes. I adapted it though to use Firmata so that I could later add temperature and light sensors so those things could be logged to some computer that acts as a 'server' to support the hydroponics setup. I'm imagining it could be web-enabled with a router-like interface to adjust grow parameters for plants: the intervals for pumping, controlling lights, etc.
For this reason I'm working on getting the Arduino to talk to an old Fon2100 Fonera router I have sitting around. I got them both happily chatting over serial using the OpenWRT firmware on the router. It comes with the Lua scripting language and I got that to sort of interface with the serial port too. So I could hopefully port Processing's Firmata host software to Lua and it could then control everything like that. The firmware already has a web-enabled interface so I'm planning to modify it so the hydroponics-related things could have such a GUI for adjusting them.
I modified the StandardFirmata Arduino sketches and put the pumping interval code in there. I wanted to have the Arduino control a critical thing such as water-pumping rather than the host computer. This is just in case the host crashes or something happens to the connection, so a thing like water which is so critical for plants does not get interrupted. I have that code hosted here and it's under an MIT license: http://github.com/nemik/arduinoponics
There is still a lot of work to do for all this but just wanted to mention it here in case anyone is curious. I'm working on it in my spare time from full-time job and all that so updates might be slow, but it's an exciting project for me.
I'd also appreciate any suggestions or criticisms on it.