Hi, is there anyone who has done a PAR meter with arduino yet? I don't have the technical skill to do it myself, but also don't have the resources to buy one.
Have you googled that already? First hit: http://www.plantedtank.net/forums/showthread.php?t=120109
Yeah I've seen that one, and it looks good but not as descriptive as I would need. My technical skills are very limited. And there are no other guides.
That's why I thought I'd ask here if anyone has done it.
That guy has done it, he has documented it and he even linked an almost perfect sensor for that stuff. What else do you need?
Just trying to get more info about it. Someone who's run out of own projects might be wanting to do one, and maybe provide a guide of it.
I am in the arduino forums right?
You are in the Arduino forums but unfortunately no matter where you go you will meet a lot of people who forget what it's like the first start and think they're better then everyone else. No question is a stupid question unless of course you're asking it on their forum. Everyone forgets that if it wasn't for people like you asking these questions over and over and over there wouldn't be so many places to go to find the answer. Sometimes it just takes a different way of explaining it for somebody that understand it.
Unfortunately I have not done anything with a par sensor but will be building one here soon for my grow. It just really irritates me when someone asks a question and the first response is have you Googled it. That just tells me they don't know the answer. Yeah I Googled it and even if I hadn't that's what forums are for.
The PAR sensor I used in college was a couple grand. Had a big wand probably lined with a bunch of sensors.
I'm not sure how it would work with an Arduino, as you have light sensors that can measure overall lux, and then photodiodes that are sensitive to only specific wavelengths. But there aren't sensors that I know of that read all present wavelengths standardized to any amplitude you'd make sense of.
Not sure how useful you're expecting such a thing to be, you can cherry pick a few wavelengths and try to find sensors in those bands, but again without any real baseline, you'd just be able to say 'yep there is some red light in that light'.
Since no one god damned answered this properly
I will amend this post with something useful...
Unfortunately that link is not useful. That link is not about building a PAR sensor, instead it's about connecting an existing PAR sensor to an Arduino.
You know, maybe not having a "proper answer" after five years simple means there is no answer? I've been looking into building a PAR sensor based on an Arduino as well. Without a working light spectrum analyser (I have yet to find one that is not the size of a piece of furniture and for lab use only) this is just not possible.
Point in case: the SQ-225 sensor mentioned in your link only works well under T5 fluorescent light... which imho makes it a terrible waste of money because if you know the spectrum of the light, all you need to do is measure the overall brightness and you can calculate the PAR!