OLcontest, modified light: 20cm fresnel lens thrower

I measured the luxvalue in the hotspot at 12.33 meter, then calculated that back to 1 meter to get the candela-value.

I’m not sure what “solid angle” is, and the sensor area does not matter as long as it is more or less uniformly lit, as is the case because the hotspot is way larger than the aensor area.

Please excuse if this is off topic, i was puzzled by the calculation. But after a little study it makes more sense—the lightmeter is calibrated to provide a Lux value for a 1 square meter area at the sensor and not just for the tiny sensor area.

Lux is a measure of the light energy hitting a target area. The units of Lux are lumens/m², where lumens is a measure of the light energy known as luminous flux, with units of cd-sr, candela-steradians. And of course area is measured in square meters.

Steradians are a unitless measure of solid angle, symbol Ω, which is the angle from the apex (light source) subtended by the area of the target.

i was assuming the target area was just the tiny sensor area, but it is effectively a 1 square meter target area. So the solid angle Ω subtended at 12.33 meters away is Ω = Area/distance² = 1m²/(12.33m)², or the target Area = Ω ・(12.33m)²/1m²

So to convert: lux = lumens/Area = candela-steradian/ Ω ・(12.33m)²/1m² ;

and solving for candela = lux ・(12.33m)²/1m²

:+1: :slight_smile:

No matter how impressive the numbers are - the bat signal trumps everything !! :laughing: :sunglasses: :smiley: Great project djozz :+1:

First class build djozz :+1:
I had no conception what a Fresnel lens can do until your build. I’m still new here and very impressed how well this works.
Every part of this build is very clean and neat. Great build work djozz :sunglasses:

Thanks, there is still little things to be done, like a name and some beamshots, I hope to do them during the Christmas holidays.

I like this! :+1: :slight_smile:

may I suggest the Dutch thrower?
Or
Throwing Dutchman?

Awesome build!
:+1:

A box of light

DSS
= Djozz’s Star Shooter

The Flying Dutchman? :wink:

Ver licht? :stuck_out_tongue:

I had to finish it today, so here’s the final stretch.

Because the star and the batman projections were not what I wanted for this build, I tried a little spider. The shape was too difficult for the fretsaw, so I went for etching a thin copper sheet, for so long that the copper was eaten through by the FeCl3. I took a long time, and the cutout was not perfect, but the result was rather nice.

Still, this was not the final version. But here are some pictures. Both are at about 40 meters.

I like the spider.

Maybe a slot for interchangable shapes

That’s AWESOME djozz. If I saw that in real life, I’d be thoroughly creeped out (I hate spiders!)

And now for the finished light!

Meet the Vir-O-blast C19. My pinstripe is certainly nowhere good enough to apply for a job at RR (link), but I still like my paint job.

The vir-o-blast c19 will not infect you, or cure you from anything (although this post may be the start of a new conspiracy theory :person_facepalming: ), but it may hopefully brighten up this dark winter a bit :slight_smile:

Without the virus stencil in place and with the led die focused, the throw number of this build is over 4Mcd, but with the led die defocused and the stencil focused, the virus projection does 800kcd, still a significant number.

And some pictures of the finished light:

Tonight I will do a small video showing the zooming action, and still some loooooong distance shots showing the 4Mcd need to be made.

I love it! :beer: :+1: :slight_smile:

You know, somehow I missed this entire entry - lord knows how. It is amazing. Personally I am not going to be happy until I see a BLF logo in that thrower lol! (kidding of course)
fantastic work, well beyond anything i could muster! Good luck!

Cool :+1:

Regards Xandre

Awesome build, Djozz! :beer:
I’m thinking about numerous images to be projected using that flashlight.

I like it ! :+1:

Haha that little viral addition takes the cake :smiley: