I emailed you.
Yes this is an open source project. Anybody can take it on.
Over at plantedtank.net, a user named Hoppy used a 3 different light filter gels to isolate the PAR spectrum even further to make it more accurate. We talked about it generally in the beginning about using filters and he's taken a lot of time to experiment.
http://www.plantedtank.net/forums/showt ... p?t=443185I think he's using a regular lux meter where you have to do some math to the output manually but shouldn't be a problem if you use an arduino.