If you use a calculator and X your reading by 0.8 it should give you “almost par” for under £20.
If anyone’s got anything they would like to add. Correct me on. Please do. I’m still learning very much but this seems a relatively simple cheap alternative to getting lighting right in your room
If you get this going, post some pictures. Interesting idea. I wonder if we could find a film that blocks those ranges. Then we could just slap it on our phones and get “almost PAR”
I’ve already ordered the parts for this. I couldn’t not at that price.
The only downside is. I’m gonna have to buy a hydrofarm one to get a comparison lol. There are certain gel filters that block out those wavelengths too so with a bit more research and modding we could have an actual bargain par meter
I dont understand one part - how does blocking the ranges you’re wanting to measure help? I would think you would want to do just the opposite? Wouldnt you want to filter out/block everything you dont want to measure and just leave those you do?
Also, how are you planning to calibrate this once its built? You would need some sort of standard to compare against wouldnt you?
The film is to block out the wavelengths that you don’t want to read you are correct I think you just misread what was said previously. And I did also say I’m probably going to have to buy a hydrofarm par meter to run side by side.
Ah, ok, I misunderstood what you meant by ‘those ranges’
Yeah, calibration is going to be the key or you are just guessing. I found the thread by visajoe1. The graphs he posted dont look good to me as far as the response/sensitivity range of his alternate diodes - with and without filters - when compared to a real PAR meter. The DIY diode has a very narrow peak that falls off sharply on either side as opposed to a nice wide, fairly even sensitivity range of a real PAR meter.
What that means is that if your light happens to have output that peaks outside that narrow range, the readings will be way off.
The best he could get with filters was this graph. The black lines are from a real PAR meter. Note that the pink lines have a big dip in the center of the range and fall off early on the red end and go too far on the blue end.
It looks to me like you’re going to have to re-calibrate for every LED, HID, etc with a different kelvin rating. I dont see how you can compare readings from different lights - for example trying to compare your HID light to a new LED light or even two different LED lights.
I can see how this would be handy for checking when you raise lower or your lights, or to check readings at the top of the canopy vrs the bottm, but a regular LUX meter will do that just as well I think.
Hmmmm - I just realized I’m being a real party pooper and dumping all over your idea. Sorry about that.
i Came here for information bro. Whether it’s what I want to hear or not is irrelevant lol. I’d like to thank you for taking the time to make me see it’s not worthwhile really but I’m still gonna do it for the laugh.
Glad that didnt come across the wrong way. Im like you in that regard. I will often get into some project more out of curiosity and/or just a desire to tinker around than any practical reason. I just bought some Sonoff switches for that reason. Didnt really need them at all, but Im want to mess around with re-flashing them and get into the Home Automation thing - plus I think they are cool
Already on the sonoff game thanks to @Robin this is my “light brain” don’t know if you seen my starting from scratch garden but build progress is going on there.
Definitely a tinkerer myself. Keeps me busy when I’m not busy lol
It can @LemonadeJoe I’ve already got the replacement diode here in a box. Just need the lux meter to arrive now. Currently soldering my last cob to heatsink
how would you go about calibrating it? it seems like a good idea though, i wonder if perhaps there’s other replacement diodes which might be better suited for this
I said earlier the only way I can think to do it is buy a hydrofarm quantum meter and go from there mate. So all in all it’s not a great idea but it’s a bit of fun and be good to see how they stack up next to each other.
There is a company that make gel filters for photo diodes which would probably be the best method of to try and knock that 20% out of range slightly back in but I can’t figure what colours or order they would need to go
there’s a chart in another thread for converting lux to PAR it has the conversion factors for lots of different light manufacturers, spectrums etc but not the ones i’m using. i think a lux meter app on my phone is good enough for my purposes, i just want to compare different areas of the canopy and also different heights etc
maybe you could 'ask your local hydro store if they have a par meter you could borrow to compare it against
Hydro shops round here won’t have a par meter. They describe led building as “just fucking about” best advice I’ve had from them is using plant magic evolution as a foliar feed. (It’s good shit and you can’t mix anything at the roots with AN really so served a very good purpose)
I digress anyway it will likely be a case of biting the bullet and ordering from the US paying the duty on it. Unless anyone has a link to a U.K. par meter my options are very limited
Great idea for DIY project… Let’s hope the diod can be refitted!
can 