I made my order in for my DIY peristaltic pump and I bought this guy too
It's sensitive to visible light and a little IR as well so I hope it won't throw the
reading too much. So yeah, it's not super accurate but maybe good enough
for the regular hobbyist.
I've already started building the waterproof body to hold the photo cell. The case
doesn't have a diffusor like a real PAR sensor but hopefully it'll be fine.
It a little plastic paint jar and wires are threaded through the tubing. The signal
will be read with my handy all purpose ardiuno...
Thanks to Hoppy's PAR chart, I can calibrate the signals to a rough guessimate.
Compared to a $300 PAR meter & sensor, this might be a deal.