wquiles
Flashaholic
My "Light Box" or poor man's Integrating Sphere ... with fan cooled HS!
The most amazing thing about this project is that I have been thinking about it since last summer. It was not until tonight that I got it running for it's intended, main purpose, so basically, on and off, I have been working on this project for over 6 months !!!
The main goal was to find a way to test LED's before I put them in lights. We all know that the LED's have certain bins of tint, voltage, and intensity, so many times we modders finish a light only to find too late that the LED was not all that awesome
Although I am not claiming that I met all of my design goals, this is what I was trying to do:
1) This Light Box (LB from now on) was conceived as my own way to test LED's against each other in a very repeatable way.
2) The LB was designed to be inmune to outside light so that I can run these tests anywhere in my house, day or night.
3) The LB had to use a power source that could be changed, so that if keeping the LED the same, I could test which driver and/or battery source would work best.
4) The LED had to be thermally stable, for at least the 30-60 seconds of a test run. The idea of course is that the testing would not damage/kill the LED under test.
5) Although soldering wires to a STAR would have been fairly easy, I wanted this setup to also work with bare emiters.
6) The LED "station" should be removable so that I could also test flashlights, even if not in the most perfect way (the LB is affected by the reflector/lens).
7) I could use almost any light meter. I have two different ones, so I made sure I would be able to test with both.
8) The LB must be fairly heavy/stable, and capable of working for years and years.
9) The LB must be movable/portable so that I could take to events and share with other flashaholics.
So here are some construction steps. Everything is glued with biscuits for long term stability/strenght:
All internal panels were sanded in between coats of white paint (4 layers), and then 2 layers of clear acrilic. The surface is not like a mirror, but it is very flat and even. Here is the outside, removable "house" prior to being glued permanently:
Aftern being glued, I used some wood dowels to make sure that the house would line up exactly in the same place every time it was used. That inner piece helps reflect more of the light and prevents ANY light from hiting the light meter directly. This LB only measures reflected light:
I made one "port hole" on the side (which when covered prevents any light from coming in) which allows me to see the LED or flashlight being tested, and allows me to see the tint of the LED which I can even photograph for comparing to other LED's later on:
Here is not-completed-yet way in which I am bringing external power to the LED:
Here is the completed setup. Yes, that is a modamag copper heat sink that has been "modified" to work in the LB. I took copper wires and trimmed them into the hole and used artic alumina to create a "fairly" even surface for the LED:
So when you are ready to test an LED, use a little thermal grease:
And then the two holders apply spring presure right onto the legs of the emiter to make electrical contact. For bare emiters, I first put a little grease on a generic star that I got some bare emiters I purchased earlier, and then put a little thermal grease between the star and the emiter. The spring presure keeps everything with the right thermal path, so I can test both stars and emiters on this setup:
A little dark since I am underdriving this LED, but here is the working setup:
and with the house in place sealing outside light:
The mating surfaces between the base and the house have thin foam pieces which seal the light when compressed by the short elastic bands:
Same setup above with the port open and with overhead lights:
and with the lights in the garage off:
So does this qualify me as a flashaholic or what !!!
Will
The most amazing thing about this project is that I have been thinking about it since last summer. It was not until tonight that I got it running for it's intended, main purpose, so basically, on and off, I have been working on this project for over 6 months !!!
The main goal was to find a way to test LED's before I put them in lights. We all know that the LED's have certain bins of tint, voltage, and intensity, so many times we modders finish a light only to find too late that the LED was not all that awesome
Although I am not claiming that I met all of my design goals, this is what I was trying to do:
1) This Light Box (LB from now on) was conceived as my own way to test LED's against each other in a very repeatable way.
2) The LB was designed to be inmune to outside light so that I can run these tests anywhere in my house, day or night.
3) The LB had to use a power source that could be changed, so that if keeping the LED the same, I could test which driver and/or battery source would work best.
4) The LED had to be thermally stable, for at least the 30-60 seconds of a test run. The idea of course is that the testing would not damage/kill the LED under test.
5) Although soldering wires to a STAR would have been fairly easy, I wanted this setup to also work with bare emiters.
6) The LED "station" should be removable so that I could also test flashlights, even if not in the most perfect way (the LB is affected by the reflector/lens).
7) I could use almost any light meter. I have two different ones, so I made sure I would be able to test with both.
8) The LB must be fairly heavy/stable, and capable of working for years and years.
9) The LB must be movable/portable so that I could take to events and share with other flashaholics.
So here are some construction steps. Everything is glued with biscuits for long term stability/strenght:
All internal panels were sanded in between coats of white paint (4 layers), and then 2 layers of clear acrilic. The surface is not like a mirror, but it is very flat and even. Here is the outside, removable "house" prior to being glued permanently:
Aftern being glued, I used some wood dowels to make sure that the house would line up exactly in the same place every time it was used. That inner piece helps reflect more of the light and prevents ANY light from hiting the light meter directly. This LB only measures reflected light:
I made one "port hole" on the side (which when covered prevents any light from coming in) which allows me to see the LED or flashlight being tested, and allows me to see the tint of the LED which I can even photograph for comparing to other LED's later on:
Here is not-completed-yet way in which I am bringing external power to the LED:
Here is the completed setup. Yes, that is a modamag copper heat sink that has been "modified" to work in the LB. I took copper wires and trimmed them into the hole and used artic alumina to create a "fairly" even surface for the LED:
So when you are ready to test an LED, use a little thermal grease:
And then the two holders apply spring presure right onto the legs of the emiter to make electrical contact. For bare emiters, I first put a little grease on a generic star that I got some bare emiters I purchased earlier, and then put a little thermal grease between the star and the emiter. The spring presure keeps everything with the right thermal path, so I can test both stars and emiters on this setup:
A little dark since I am underdriving this LED, but here is the working setup:
and with the house in place sealing outside light:
The mating surfaces between the base and the house have thin foam pieces which seal the light when compressed by the short elastic bands:
Same setup above with the port open and with overhead lights:
and with the lights in the garage off:
So does this qualify me as a flashaholic or what !!!
Will
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