Lightbox, XML-2, and some extreme numbers

well it seems all have a light box apart me so …. i have to make one too :bigsmile:

problem is that i do not want to spend to much money and time on this project, so start to look around in my mess that i call office and doing so go in thinking mode … :expressionless:

…. theory is… well lets make it simple. i wanted fast and easy results. this could easy led me in wrong and false results but I try this route nevertheless.
i got not a sphere but a simple box :X (easy and fast—- check )
I got not an super duper multi-output super precisely calibrated expensive power supply, but a simple 10$ driver (easy and fast —check)
I got not a super expensive lightmeter but just the most simple one there is (easy and fast —- check)
well i didn’t think before that all i needed building my light box was there near to me …
for almost an hour all the project was finished:

sorry that i do not have photos during building process but since i thought this will fail to work, i do not make any, but since wanted to play around continue the work :stuck_out_tongue:
well i got some numbers lets see if they are worth it or are terribly wrong as I was afraid during building.

well curious i go to my crappy pc and since i do not have exel (i just boot from an live disc that i have make some time ago with some pupy OS of some sort …)
opened calc program and start learning how to use it…
after some time i got this:

funny thing it looks OK to me !
lux numbers are as i sow in my lux meter without any converting factor lol i am lucky some time

i see 133 lux in my lux meter , than those mus be 133 lumen hahaha :stuck_out_tongue:
ok i got Vf till the moment led was of, and i got some extreme numbers just for funn
i think the real Vf maybe can be 0.07 V lower because the way i measure … however here the graph from my experiment :

Output of XML-2 U2 in my super simple setup

Vf on the LED

and since i got some very small numbers here the graph in different scales to see better the values :

somewhere between 2.341V and 2.130 the led stop emitting visible light. on 2.341 V the light was very very soft :

i measure also mu M2 with this numbers : low 35, med 180, hi 240 and and say to my self oh crap this light box is totally worthless :
than i suddenly realize that maybe battery was down. opened measure battery: 3.2V ! lol got an Sony hi-drain in and : ~35. ~300 med , ~740 hi.
as u can imagine smile was back in my face :bigsmile:

Hi Ervin , great work , but one thing about the box that I can not ignore.these are designed to reflect radar waves straight back to where they came from.That is what the corners of your box are trying to do as well - not good at all :stuck_out_tongue: Even sticking triangles of card in the corners should help break up any direct reflections.Try testing with a flooder and a thrower(not zoomies)of similar output to see what results.Not trying to make extra work for you :wink:

Hi Billy X, I am not sure how the corners of my box are interfering with my measurements. probability the box will give different numbers for the same amount of light come from a throw beam and a flood beam? i measure my led lenser p7 zoom out and throw and get exact the same number 25. than i took the tir off and measure again only the led , 29. if we assuming that the head with tir optic introduce some loses it looks like the margin of error in the box is smaller than 10%. to tell the truth i expected to perform much worse. before i was planing to go pipe route or even to make a proper sphere but so far the results are more than enough to me.

Hi Ervin , have you tried ceiling bounce tests?Mine is in my bathroom , no windows , with the lens 20 cms above my washing machine lid(SI standard 1246577013124732kjdsbffhfuiezq) :smiley: .If your box is no more accurate than that….rip it up and throw it away |(
Seriously ,; I am getting 25 lux per lumen on my very amateur(and cheap) sphere.That is 25000+ lux from my 2 EE X6’s with LG cells (HE 2 and 4.35v) at 1000+or- lumens.Djozz is getting similar results post 38 .The Pipe dream guys see post 47 , are also getting low candela readings.That means a low light sample so inaccuracies (say between warm and cool tints) may well be highly exaggerated.

Those low amp numbers will come in handy one day I can feel it, thanks.

I think you can get rid of that first vf graph, it seems to be redundant.