I recently installed this free app onto my android: https://play.google.com/store/apps/details?id=com.homestudio.ppfdmeter&hl=en_US&gl=US
Seems to respond appropriately to light. While I am sure this is not dead nuts accurate considering free app and standard light sensors on phone, I would love to know how close it is to a real meter. Can anyone with a real meter do a rough comparison? Thanks in advance. Steve
I don’t have a “true” meter to compare with, but I have found a lot of these apps to be good references. You’re 100% right, rarely are they accurate, but they will produce the same reading in the same intensity of lights. So when you measure and it always reads a 40, but the pro metro reads 45, and you check the difference of numbers in multiple locations of your grow, you get a feel for the mathematical adjustments to make to get accurate readings with your less than accurate meter…… which I know is what you are saying, but I wanted to spell that out for some others. I hope you get the answer you are after 🙂
To piggyback on Chad, I don’t have a Par meter either I bought a $30.00 lumen/lux meter which I use in conjunction with an app. I tried my old IPHONE 9 not even close.
I select the 4000k CREE which matches my light spectrum. This gives me my PPFD which I put into another app to calculate my DLI.
I have tested one of my calculations vs a guy online who had tested my exact light with an Apogee PPFD meter and the results were strikingly close.
Lights are off now but I will test my lux meter and IPhone calculations vs same inputs into your app if possible tomorrow and post, hell we may learn something and we may not. Happy Growing 🙂
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It’s based on your spectrum of light for one thing. So if the app has the same light spectrum that would be the first thing to look at. Lots of custom light spectrums being built so less likely to match exactly. Also it’s just a conversion from lux which your phone can read to the ppfd using a formula. You might try to download some other lux based apps to see if your getting a consensus on the lux reading.
Here’s a website with similar conversion.
I like to use these apps to see where the light drops off and to measure light levels when I’m experiencing light burn so I know the plants limits.
Thanks for waveformlighting website calculators. I know lumen meters are pretty cheap, so maybe this is a good compromise. I saw someone using a ppfd meter in one of the Dude Grows episodes a week or so back. Anyone know what brand that was?
Probably an Apogee meter. I tried your app but was unable to down to an IPhone.