How reliable are Lux meter apps on smartphones?

Seems like a pretty neat (and free) tool that will help with measuring. Is this reliable to use or is it a bit of a gimmick? Please let me know what your experience is with it and also what Lux level's you would recommend for an autoflower in veg. Peace

Don't have the app. Sorry.

Offmymeds said:

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Don't have the app. Sorry.

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Thanks bro, fyi the app is free on the app store!

I think they're helpful for new growers to avoid light burning their seedlings.

It always amazes me how people will value the convenience of an app over the privacy of their contact's names, numbers and email addresses.

Just Be said:

It always amazes me how people will value the convenience of an app over the privacy of their contact's names, numbers and email addresses.

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All your info is already out there in todays technology

salmonetin said:

Saludos desde Tenerife

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Nice.
Funnily enough @cobshopgrow and @end_of_the_tunnel were talking to me about something similar a couple of days ago.
I'm sure they'll be interested
Also a diy sphere to catch all the photons.
The apogee has quite a large surface area to catch more light compared to a phone sensor, maybe?

Seven.

Moflow said:

Nice.
Funnily enough @cobshopgrow and @end_of_the_tunnel were talking to me about something similar a couple of days ago.
I'm sure they'll be interested
Also a diy sphere to catch all the photons.
The apogee has quite a large surface area to catch more light compared to a phone sensor, maybe?

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cant give salomentin a like, so i give it to you.

maybe you all saw it allready, but this one is ouite informative too.
if you take the lux from the video and compare it to the par value by a converter numbers can be quite wrong.
lets take 33000 lux 4000k.
above video, par meter 4000k color temp, 33000lux are 507ppfd.
33000 lux 4000 high dri are 588ppfd (not so bad!).
QB288 V2 4000K, 33000 lux are 474 ppfd (not bad either!).

if we take the recommended factor of 0.015 from the guy above, 495ppfd, quite near.

shane, migro say 0.025 (while using another lux meter type!), 33k lux would be 825ppfd then.


so better check which luxmeter you use and use a conversion factor for exactly this meter is your best bet ill say.
and if youre using 660nm leds too its not really to convert as this wavelengh is hardly captured by a lux meter.

Depends on your phone's photo sensor. Some phone sensors top out at 30k lux, so that's not too helpful really.

@Moflow you may wanna share your used phone model? your readings seems to be fine.

this seems to work with a difuser and a iphone.

I used to think they were about as accurate as the cheap lux meters, but according to this they are all over the place.

Solid lines are the reference intensities which the cellphones were trying to measure.


Edit- can't seem to figure out why they didn't plot all the different apps intensities. Maybe they were literally "off the chart"? Or maybe I'm misinterpreting somehow?

I measured with the App on a Samsung galaxy S2 tablet

@salmonetin 's reply his been redracted for some reason.....?
I think it's happened before for him.

Moflow said:

@salmonetin 's reply his been redracted for some reason.....?
I think it's happened before for him.

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I think he deletes them himself.

Android has a shitload of different models& bom.......I could see a dedicated app for ios being better

So what lux parameters should led be same as that chart everyone uses?

with the paper diffuser i would trust the apps to compare light sources, assuming you're using the same app, same phone, same paper across light sources.

4 same model iPhones...

The article goes on to talk about identical component tolerances (typically you buy 1%, or 5%, or 10%, tolerance components, meaning there's a measured +/-% of variation within all the components of the same model/specs for a given tolerance rating) and how it may be the culprit.

"We suspect that the reason for these fluctuations lies in the tolerances of the components built into the phones. These are tolerances which the user does not notice in everyday use but which in direct comparisons have a great effect on the displayed illuminance values."

"Even when using the same app in structurally identical smartphones different measuring results are achieved.

Therefore apps are unfortunately not really of any great assistance for measuring illuminance and not even any use to obtain a general idea of the illuminance value. On the contrary: They lead the user in the completely wrong direction."

Not trying to beat a dead horse, but I figured I'd just throw up a bit more of the data to help give a better picture. Idk this company or their credibility, ect, and they obviously haven't tested every make and model with every app. But their conclusion is technically sound imo and if the data is as consistently inconsistent across other makes and apps then I'd suggest not putting a ton of merit in what the app reads back??

I'd be curious to see some pictures of members cellphone apps & corded luxmeters side by side and measuring lux at various heights ect. See how well they maintain proportionality. If the % difference between the 2 device's readings changes drastically with varying height/intensity then it would support the websites findings. But if they seemed to scale at the same rate, then I'd wonder how accurate the lux meters are, as well as the websites analysis. Without a known reference value to compare the readings to, then idt we'd actually be able to tell where the discrepancy is found (within corded lux meters or within the websites analysis), but there may be ways of teasing it out if it so happens that the 2 devices measurements seem to maintain a ~static % difference (if you like to go down the rabbit hole lol).