Match's Mods: Homemade Integrating Sphere

The sphere top and bottom halves were originally two large round thermoplastic salad bowls.

I did, about a month ago

I also recently shaved, have considered selling a few lights, and started a new health regimen

i think you could make more of your spheres and sell them for profit :slight_smile:

The one i built above took a bit of time to build, not sure if there is any profit in it for the time and parts used.
I have it calibrated very well now though.

But you can undercut professional model prices by a huge margin, perhaps by more then 90% :wink:

This would not likely be close to as accurate to a professional “laboratory” Integrated sphere.

Of course, but since we like budget, a reproducible integrating sphere will suffice just like a Convoy will suffice vs a surefire :smiley:

I think you should create a build thread for your device, i am curious where you got those salad bowls

I thought it did, but realized that i never did a build thread on it yet.

Nice work DBSAR! It looks very handy with all the mounting options around it.

The accurateness of professional spheres has much less to do with the actual sphere, much more with the better measuring equipment and calibrated sources, a home made sphere like we make already has excellent integrating properties.

Good point. for most of us the only way to “calibrate” our Integrating Spheres is calculations based on testing our stock known ANSI measured Lights, in my case is a few fenixes, Nitecores, Olights, thrunites, etc.

Modding flashlights to advanced for me but messing with papier maché I am in!

For the purpose of consolidating information regarding IS's here are a couple of links for those who may be interested in a source for Barium Sulfate products for the inside coating if one were to choose that method.

This is just one supplier that was mentioned in another forum. It is not known if they are more or less expensive than any others.

Labsphere, Inc.

A Halma Company
P.O. Box 70
231 Shaker Street
North Sutton NH US 03260
+ 1.603.927.4266 (ph)
+ 1.603.927.4694 (fax)
labsphere@labsphere.com
www.labsphere.com
And their coating products page: http://www.labspherestore.com/category-s/8.htm
as well as a highly technical data page about their coatings: http://www.labsphere.com/products/reflectance-materials-and-coatings/white-coatings/6080-white-reflectance-coating.aspx
Best wishes

Well… I found a globe …:slight_smile:

great idea. thanks!

Welcome to BLF!
Match’s coating was plain flat white paint without BaSO4 what I remember, but his sphere was made many years ago and Match is not around here anymore.
A BaSO4 coating can indeed be 0.96 if done well, but I doubt that DIY formulations containing BaSO4 will be anything close to that, and even if someone did a good job at it, the experiment for testing the reflective value is difficult without proper laboratory equipment. And then you also want to measure the reflectivity across the spectrum…

I don’t really understand the concepts behind an integrating sphere, I wish there were an affordable one just because I’d like to test my mods. This would certainly be reflective, but aside from putting a hole in it ruining the structural integrity/shape I assume there are many other reasons it wouldn’t work that I’m unaware of. https://www.amazon.com/TONIFUL-Hangable-Aluminum-Metallic-Decoration/dp/B07X655671

Seems like there is a decent market for this and data logging light meters, I’m mildly surprised we don’t see some package deal priced well out of China.

If you are willing to pay loads of money for shipping from EU, you can get a 50 CM (around 20”) eps ball that makes a fantastic sphere. They’re about $40 US, but shipping will easily be that much. That will handle reflectors up tp 110 mm and many tens of thousands of lumens. I have a 30 cm one I use for testing and it’s great. You need a calibrated light or one of verified outout to set the multiplier for getting your relative lumen values, but once calibrated, you can get very close (5-10%) to the actual output. Djozz has a great tutorial for it on here to where you don’t need a baffle, ND filter or diffuser…you measure the light through the wall of the sphere and that works. Mine is only good for reflectors up to 65mm, so I built a lumen tube. Point is, there are options for integrating devices that don’t cost hundreds or thousands of dollars.

Thanks. I really should make one some day.

I see people referencing calibrations. I am sure it would take me a long time to catch up on the people and their methods, but would a sphere like that get me at least 5% precision?

If under a couple hundred total cost, time tweaking and learning is my concern, though I can totally see enjoying that process.

It’s worth it in the long run. It took me probably 10 flashlights (including a loaned Makkua calibration light) and several hours of work to get my multiplier/calibration right. You need to test different sizes and types of reflectors, flooders, throwers, different tints and cri to get it dialed in. I found Fenix, Thrunite, and Olight are good samples to test your calibration with since they use constant current drivers for consistency and their factory numbers are pretty trustworthy. I think 5% is a bit far out, but not impossible. Generally, 10% is considered acceptable and totally realistic. Just be patient and take your time, have fun with it.