Integrating sphere #4 (the fast and cheap one)

93 posts / 0 new
Last post
garrybunk
garrybunk's picture
Offline
Last seen: 4 hours 34 min ago
Joined: 10/31/2011 - 09:25
Posts: 6068
Location: Johnstown, PA

So the “correct” lux reading will be the “max” number while sliding the light in and back out?

djozz wrote:
It just occurred to me: -the measuring range of the 15cm sphere of the OP is 0-17,000 lumen (which is a useful range) -with the same build, a 30cm sphere (with the same 2cm wall thickness) would have a range of 0-68,000 lumen, which is less useful because you will never measure this high output, and the resolution at the lowest light levels gets too low. -to solve that, you could slice the wall of the sphere thinner at the position of the detector (actually like I sliced a bit off the sphere where I made the entrance hole), before attaching the ring, this will get more light to the detector and therefore bring the range down. So you can adjust the range by slicing more or less styrofoam off at the detector spot, and I can not think of a reason why this would affect integration in a grossly negative way.

Like tigris99 posted at MTBR (not sure if he posted it over here). Pic:

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques


NOTE: Moving my photos from PhotoBucket to Flickr. PM me or post in the thread if you can’t see my images and need me to fix or send a gallery link. PhotoBucket images should remain visible until November 2018.
Muto
Offline
Last seen: 15 min 22 sec ago
Joined: 09/04/2012 - 16:42
Posts: 2178
Location: Southeast, PA

Here ya go, funny how we call big lights Chunky Monkeys. This is fitting (in more ways than one)

 photo SoupCan 001_zpstmkckblq.jpg

Just tried this on a whim and Waalaa!
This can fits the Courui D01 light perfect and the inside rim should be helpful for using adapter rings for small lights.
Will get the can cut and set up the sphere later this week.
Enjoy!
Keith

After the Apocalypse there will be only 2 things left alive, Cockroaches and Keith Richards
..

Big Sky Country
..

No matter where you go, there you are.

garrybunk
garrybunk's picture
Offline
Last seen: 4 hours 34 min ago
Joined: 10/31/2011 - 09:25
Posts: 6068
Location: Johnstown, PA

My integrating sphere (or as my 3yr old says, “integrating spear”) is nearly complete. I started using duct tape instead of aluminum tape but then realized the duct tape lets an awful lot of light through it, so I used black electrical tape over the duct tape. Some pics:

The hole ended up at 90mm and tapered in (hope that doesn’t hurt me):

Created an indent for my luxmeter sensor which made it start to look like the Death Star Smile :

Dug out some more “foam” to get the sensor to sit in place a little deeper and make it easier to get in the same location each time:

Luxmeter sensor in place (will likely add velcro strap):

Taped up entrance hole:

The way it will look once finished, after mounting two sections together and attaching to the base:

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques


NOTE: Moving my photos from PhotoBucket to Flickr. PM me or post in the thread if you can’t see my images and need me to fix or send a gallery link. PhotoBucket images should remain visible until November 2018.
garrybunk
garrybunk's picture
Offline
Last seen: 4 hours 34 min ago
Joined: 10/31/2011 - 09:25
Posts: 6068
Location: Johnstown, PA

Didn’t want to clutter this thread, so I asked for help with my calibration in a new thread.

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques


NOTE: Moving my photos from PhotoBucket to Flickr. PM me or post in the thread if you can’t see my images and need me to fix or send a gallery link. PhotoBucket images should remain visible until November 2018.
djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

garrybunk wrote:
Didn’t want to clutter this thread, so I asked for help with my calibration in a new thread.

-Garry


I will post there tonight, have to prepare dinner first! (chili)
ToyKeeper
ToyKeeper's picture
Offline
Last seen: 1 hour 45 min ago
Joined: 01/12/2013 - 14:40
Posts: 10147
Location: (469219) 2016 HO3

I’m kind of pondering adding a reference light to this design… I have a ZL SC52 with very consistent output, and could either make a separate hole sized just right for it… or perhaps give it an incomplete slot with the last bit of the hole still filled in by foam. Not sure what the best approach is.

Which of these do you think would work best?

  • No reference light.
  • Reference light slots in completely so it’s visible from the inside of the sphere.
  • Reference light slot stops early so the light must pass through a thin layer of foam to enter the sphere.

I also have a few reference lights to choose from… will figure out later which might work best:

  • ZL SC52 (most stable, but widest… and a weird shape)
  • L3 L10-219
  • L3 L10c-219
  • TN T10T NW
  • ET D25A Ti

The tail clicky on the last three might be a big advantage.

CRX
CRX's picture
Online
Last seen: 9 min 29 sec ago
Joined: 04/02/2013 - 15:27
Posts: 3995
Location: Scotland

Hey so i finally had a go at making one of these, thanks for the thread djozz Thumbs Up
Both the luxmeter and styrofoam ball arrived this morning, love it when that happens Cool

This is completely new territory for me so any tips or guidance is welcome.
What i have is a 200mm sphere with 15mm walls, a 40mm cutout and the cheap meter.

Now i need to figure out how to use it… LOL

.

.

Nearly all of my lights are modded except two so finding calibration lights is difficult but one of the stock lights i have is the Acebeam H10 which appears to have fairly steady regulated output of around 1000 and 2000 lumens.

With the Acebeam on high i get a reading on the 20000 scale of 490 (x10) and turbo sees a 980 (x10) reading so coincidentally i’m basically doubling the screen result to get the rough lumen output which should be around 1000 and 2000lm respectively?
Or should i be applying some formula?

The Klarus Mi7 shows 260 (x10) on high and 33 (x10) on low mode, which when doubled gives 520lm and 66lm – not too far off these results

Thoughts?

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

All looks fine to me Smile

CRX
CRX's picture
Online
Last seen: 9 min 29 sec ago
Joined: 04/02/2013 - 15:27
Posts: 3995
Location: Scotland

Cool, this is going to keep my free time busy for the next few days Smile

garrybunk
garrybunk's picture
Offline
Last seen: 4 hours 34 min ago
Joined: 10/31/2011 - 09:25
Posts: 6068
Location: Johnstown, PA

Tips from my experience (and I’m certainly no expert):

Not sure about how your luxmeter mounts, but the way mine is it’s easy for the readings to change based on how tightly it’s held against the foam ball (mine held with velcro strap which can be seen here. So what I’ve done recently is borrowed the Fenix headlamp I originally used for calibration and used it to calculate “known values” to hold on my own “Calibration Check Light” which is simply a Convoy M1 XP-G2 with 6×7135 AMC’s. It’s low & medium modes are very steady, high can vary greatly so I don’t hold the high number (I would suggest using lower modes for calibrating & not trust extreme outputs – even the Fenix light varied in “Turbo”). I now plan to reserve this light for only sphere calibrations / checks. My multiplier does change, but not drastic. I often compute a multiplier from the average of a few steady output lights. I’m finding medium modes (i.e. like 200 lumens) seem better than trying to hold really low values (1 to 20 or so lumens).

Create a spreadsheet for your lumen calcs and run your computed multiplier back against all measurements so you can see how your “check lights” hold up and how consistent they are. I’d be glad to email you a copy of my latest Excel spreadsheet if you want. There’s a screenshot of my old one at the O.P. of the link given above. Record your measurements at startup & @ 30 Seconds (and I make note how stable the readings are). Use a timer (I use a kitchen timer or my phone and set it to 33 seconds which gives me 3 seconds to get situated after tapping “start”).

Should go without saying, but always test on full batteries and make note which batteries you used and voltage (helps when your confused over low or different readings taken a month or year prior!).

Measure highest modes first while batteries are fresh and give some the batteries some “rest time” between measurements.

Most importantly – be extremely consistent with where you align the head / lens of your lights during measurements. I eyeball (best I can) that face of my light is always aligned with the bottom level of my entrance hole.

Cover you sphere with a large shopping bag (or whatever) when not in use to keep dust off and out of it.

I still have questions about the use of mine & values I am calculating (for instance some lights in high modes seem to give me much lower values than I expect).

You should buy or borrow a good “known value” light (like many Fenix lights) to get your calibration nailed down correctly.

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques


NOTE: Moving my photos from PhotoBucket to Flickr. PM me or post in the thread if you can’t see my images and need me to fix or send a gallery link. PhotoBucket images should remain visible until November 2018.
CRX
CRX's picture
Online
Last seen: 9 min 29 sec ago
Joined: 04/02/2013 - 15:27
Posts: 3995
Location: Scotland

Good tips, thanks mate Beer

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

garrybunk wrote:

Most importantly – be extremely consistent with where you align the head / lens of your lights during measurements. I eyeball (best I can) that face of my light is always aligned with the bottom level of my entrance hole.

In this design it is better to align the face of the light with the top level of the entrance hole, in that position there is no direct light going from the flashlight to the area where the sensor is, which should give better integration.

But it is insightful to compare the readings of both positions, if the ratio of both positions is the same for a flooder and a thrower, it is apparently not so critical what the best position is (but as Garry said, decide on a consistent position).

DeJaVu
Offline
Last seen: 1 month 3 weeks ago
Joined: 10/15/2016 - 17:55
Posts: 24

Great idea and even better ease of making it. Kudos to you Djozz for the guide.

Planing on making one with a 200mm ball, with wall thickness of 23mm. Now as my biggest lights are Convoy L6 and Couroi D01, i would need a 76-77mm hole to be able to measure them and similar sized lights.
Will i get away with a 77-80mm hole on the ball im planing on using, or there is just no way and i should try and find a ball with bigger diameter?

Kame Sennin
Kame Sennin's picture
Offline
Last seen: 1 hour 19 min ago
Joined: 09/24/2018 - 14:38
Posts: 317
Location: France

Waking up some sleeping beauty but this cheap integrating sphere is really something nice and as i am making one (well ... actually several as i found a  source for 20cm and 30cm polystyren balls not far from where i live) i have some questions about possible upgrades.

 

Do you think that adding some kind of diffusion layer (frosted glass, dc-fix, ...) inside the ball at the entrance hole would help reduce the reflectivity variation from one flashlight to the other ?

Of course it won't be perfect because some of the light will be reflected from the diffusing thing back to the flashlight where it will be reflected again and it will reduce the light entering the sphere too but i am wondering if the overall result could be better

Has someone already tried that ? what to expect ?

 

Mmmm maybe the only way to know for sure would be to add a ref light and once you have one installed you don't need that much to reduce the reflectivity variations Wink

 

 

TheOnlyDocc
TheOnlyDocc's picture
Offline
Last seen: 4 months 2 weeks ago
Joined: 06/26/2015 - 05:17
Posts: 949
Location: Mönchengladbach /Germany

I was watching a doku about LED light (danger of the blue part. . . .and other effects on the body ). When this nice integrating sphere came up.
And i was thinking the 40cm sphere i was planing is bulky Big Smile

New WildTrail (former LuckySun) D80v2 Sale has Started http://budgetlightforum.com/node/66255

DominikM
Online
Last seen: 9 min ago
Joined: 05/02/2016 - 17:40
Posts: 34
Location: Wroclaw, Poland

I have 50cm at the office, it’s just enough for torches Sad

When I’ll have a load of money and a big house I’ll buy this one :

Cool

Enlightened member of pl.rec.rowery

Light-Test.info – bike light’s & Headlamps comparison site. – In polish but picture says everything

MRsDNF
MRsDNF's picture
Offline
Last seen: 5 days 6 hours ago
Joined: 12/22/2011 - 21:18
Posts: 13141
Location: A light beam away from the missus in the land of Aus.

TheOnlyDocc wrote:
I was watching a doku about LED light (danger of the blue part. . . .and other effects on the body ). When this nice integrating sphere came up.
And i was thinking the 40cm sphere i was planing is bulky Big Smile
!{width:70%}https://i.postimg.cc/Bv9FSDyd/Sonntag-31-M-rz-2019-10h40m37s-001.png!

We should chip in a few dollars each and buy this for djozz. I’m sure he’d fit it into his unit somewhere. Silly

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

MRsDNF wrote:
TheOnlyDocc wrote:
I was watching a doku about LED light (danger of the blue part. . . .and other effects on the body ). When this nice integrating sphere came up.
And i was thinking the 40cm sphere i was planing is bulky Big Smile
!{width:70%}https://i.postimg.cc/Bv9FSDyd/Sonntag-31-M-rz-2019-10h40m37s-001.png!

We should chip in a few dollars each and buy this for djozz. I’m sure he’d fit it into his unit somewhere. Silly

We’re not using the bath very often, I can break it out and place the sphere there, squeezing ourselves past it to reach the shower. But we can’t afford to shower anyway after I bought that thing.

Best integrating bathroom in the world.

cabfrank
Offline
Last seen: 7 hours 5 min ago
Joined: 11/19/2010 - 17:25
Posts: 2977
Location: healdsburg, california usa earth

Too much information, but I do the ceiling bounce test in the bathroom quite often at night, so it makes sense to me.

TheOnlyDocc
TheOnlyDocc's picture
Offline
Last seen: 4 months 2 weeks ago
Joined: 06/26/2015 - 05:17
Posts: 949
Location: Mönchengladbach /Germany

If we can get him a even bigger one the space problem goes away because he could move directly into it.
A bit cold in the winter but during the day he could use the calibration quartz tungsten halogen lamp to heat it. Cool

New WildTrail (former LuckySun) D80v2 Sale has Started http://budgetlightforum.com/node/66255

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

TheOnlyDocc wrote:
If we can get him a even bigger one the space problem goes away because he could move directly into it.
A bit cold in the winter but during the day he could use the calibration quartz tungsten halogen lamp to heat it. Cool

Preventing my son sticking his dirty fingerprints on the wall will be a daytime job. “Get your f#lthy fingers off my wall, you’re ruining my multiplier”
-X3-
-X3-'s picture
Offline
Last seen: 5 hours 37 min ago
Joined: 07/16/2014 - 03:28
Posts: 2723
Location: France, Angers

Here’s mine, 20cm in diameter :

I made the entry aperture the size of a C8 bezel and coated it with some black electrical tape.
I have some quite good measurements, but I don’t have many stock flashlights unfortunately… I tend to mod any new light that comes in my collection Innocent

Anyway, I average my multiplier with a dozen stock lights, and then apply it to my measurements.
I’m glad to have tested it, but now I kind of regret to not have bought the 30cm version (11€ vs 5€…)
Well, I guess I’ll buy it to measure some bigger lights.

Here is a spreadsheet I made to compile my results.

"-X3-, is there any place in your house without a flashlight ?" 

My Flashlight public album (mods, emitter swaps, eye candy)

My reviews channel (French language, Olight, Thorfire, Sofirn, Lumintop : 60+ lights tested)

My personal channel (including Olight SR mini, S1, S2, S1A and S-mini disassembly)

M4DM4X blog, saves you $$$ 

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

Looks good X3 !

Your calibration leans on the published numbers of Olight, I’m not sure how they compare to real lumens. But the multiplier at least does not show enormous deviations so that looks trustworthy.

-X3-
-X3-'s picture
Offline
Last seen: 5 hours 37 min ago
Joined: 07/16/2014 - 03:28
Posts: 2723
Location: France, Angers

djozz wrote:
Looks good X3 !

Your calibration leans on the published numbers of Olight, I’m not sure how they compare to real lumens. But the multiplier at least does not show enormous deviations so that looks trustworthy.


What bother me is my Eagletac D25A 219C… I have a multiplier of about 4 with this one Sad

EDIT : I don’t know how Olight round up their numbers, but I do know that they own an integrating sphere (maybe 1m in diameter) as can be seen on the office/factory tour that Marshall did a few years ago

"-X3-, is there any place in your house without a flashlight ?" 

My Flashlight public album (mods, emitter swaps, eye candy)

My reviews channel (French language, Olight, Thorfire, Sofirn, Lumintop : 60+ lights tested)

My personal channel (including Olight SR mini, S1, S2, S1A and S-mini disassembly)

M4DM4X blog, saves you $$$ 

robo819
robo819's picture
Offline
Last seen: 1 day 2 hours ago
Joined: 03/10/2015 - 21:20
Posts: 1885
Location: Deep East TX

Made from 4 inch , schedule 80 PVC “P” trap and 90’s and with a .05 (or 1/2 of actual reading on meter) comes in about 3% under what the Maukka calibration lights show.

The cut out on the side of the top opening , is so that headlamps or other 90 degree lights can be centered for testing. Also have different sized foam cut outs , from 3/4 inch opening up to almost 4 inch to block any light from escaping the opening.

Below are the pictures of the light tube and under those , the Readings Muakka had on his integrating sphere and my actual readings from my light tube set up with those same lights.





Click any link to see MY REVIEWS:

Maxtoch M24 Sniper / Maxtoch 2X Shooter (2016 factory dedomed) , 2X - XHP 70.2 / Maxtoch Xsword / M1 Archer *** ### ThruNite // Archer 2A V3 / Ti4T / TN4A HI / TH10 / TH20 / C2 Mini / TC12 V2 / T01 /  , neutron 2C V3 , TC20 / Catapult V6 / TC15 / TC15 CE *** ###  Olight // H2R Nova , S10R III / S30R III / H1 Nova / H1 R Nova / X7 Marauder , PL Mini ,  M2R warrior //// Orca T11 / Nitecore EC20 / BLF A6 / Custom Convoy C8 / Lixada Triple 3800LM / Lixada 1000LM / LuxStone X30 / Manker E02 / Manker E14 II /  ### Thorfire /// PF03PF04 , Upgraded PF04 , C8 , S-50 ,  VG-10 , VG25 , C8s , BL30 , TK4A  , S1 , VG15 S  , TK 18 //// ##WowTac// A4 , A1 (original) , A2 headlamp , A3 //// Acebeam L16 /// Massdrop (Lumintop) Brass EDC

lelea
Offline
Last seen: 3 months 1 week ago
Joined: 10/18/2019 - 07:53
Posts: 7
Location: Denmark

Hi Guys! I read all comments on this beautiful thread. I got curious and I registered, so I am new here!
Is there a welcome cake or something? =D

I was wondering what power could such integrating spheres sustain. what if I plug in a 10W halogen lamp?

Cheers!
Lorenzo

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

Welcome to BLF lelea!

We have no cake but we do have Milla, if the Raccoon chimes in that is.

Not sure about the halogen inside a styrofoam sphere, 10W sounds still ok for a single measurement but do not do a runtime experiment with that. I have coated a few spheres with latex paint mixed with bariumsulphate, I think those can handle some more heat than bare styrofoam.

lelea
Offline
Last seen: 3 months 1 week ago
Joined: 10/18/2019 - 07:53
Posts: 7
Location: Denmark

Thank you Djozz =)

did they end up collecting money for a larger bathroom with a larger integrating sphere for you?

Unfortunately I have to run long measurements and it has to last “forever”. The point is also to be able to change the lamp when it dies without messing with alignement.
I will think about painting with latex. maybe it’s worth doing a test! In that case is it even necessary to have the foam sphere? I could paint any other material, right?

How should I think about efficiency of integrating spheres in terms of input-output power? If my lamp is 10W how much should I expect to have as output?
Right now I use a lens to collect some of the light, thus I lose most of the source power. To calculate how much I can just compare angle of illumination with size of the lens, but what about the integrating sphere?

Thanks again,
Lorenzo

djozz
djozz's picture
Offline
Last seen: 3 hours 29 min ago
Joined: 09/07/2012 - 17:04
Posts: 16439
Location: Amsterdam

There is zero chance that I will have a larger bathroom, it implies moving house inside Amsterdam which is virtually impossible with the current crazy housing market. And even if it came true, it will be my girlfriend’s domain, not mine, my hobby is doomed to be restricted to the dark corner behind the cupboard. Steve

Painting with latex may make a styrofoam sphere a bit more heat-resistent. I experimented with a PVA-bariumsulphate mixture too (PVA=polyvinylalcohol), that handles a bit better even and should give a better (more constant reflectivity over all visible wavelengths) coating too.

But there is no other reason to start with a styrofoam ball than easy availability, if you can find a sphere from any other material and give it a flat white coating on the inside, you are good. I hope to find an affordable nice metal sphere at some point, that should handle any output power.

It is a misconception that input-output efficiency plays a direct role in integrating spheres. It does not matter if the sensor picks up only a tiny fraction of the input power (which indeed it only does), it can be any fraction as long as that fraction is the same for all colours and output directions of the light source. Your multiplication factor then takes care of the correct calibration. The only reason that you want high reflectance on the inside of your sphere is indirect: high reflectance causes more reflections before the light is finally lost or reached the sensor, and more reflections equals better integration.

(As a side note: I suspect that most people on BLF have no idea what light integration is, and even if they have a clue, why it is an important feature of your device in order to measure light output. I hoped that my threads on integrating spheres would help a bit but it does not seem so.)

lelea
Offline
Last seen: 3 months 1 week ago
Joined: 10/18/2019 - 07:53
Posts: 7
Location: Denmark

I see your point about integration. Maybe I should have pointed out I am most interested about power output than most people. I am considering using a sphere to “save” energy from a halogen lamp that I need illuminating an optical setup. The setup only takes few mm rays, thus now most of the light is lost shining elsewhere. An integrating sphere with a homemade output slit will give me the ability to change lamp without realigning the setup while using somehow all the light from the lamp, even tho I have no clue what would be the efficiency I get out.
Maybe a new thread is due for me =)

Pages