Smaller LED 12 Volt Chip For DIY ?

[MEXICOWANDERER]

On the surface this thing looks like a cutie. Available in (3) color temps, reasonable wattage to make rational heat-sinking area a reality, and it's the latest technology from CREE.

I have big heat sinks, but a lot of rigs cannot tolerate that.



http://www.ebay.com/itm/1piece-6V-12V-Cree-XPG2-XP-G2-3535-4Chips-18W-LED-Emitter-on-20mm-Copper-Sta...

[MEXICOWANDERER]

:B

I really *really* try and keep my LED projects sane and usable. 1,000 watts at 35 volts is 28.6 amps. It doesn't take a genius to figure out it would take an 8-D LiPo battery to make runtime feasible with that "flashlight"

You are looking at perhaps a thousand dollars worth of parts. Another "Guinness Book Of World Records" wannabe.

[Bend]

Someone else must be reading Mex's LED posts:

https://www.youtube.com/watch?v=-JVqRy0sWWY

8>)

[MEXICOWANDERER]

The 1st level tree canopy sees lots of lumens. 2nd tier, less, where I live on the ground, noon is twilight. In the tropics there is no twilight at sunset. One minute there's light, the next, you'd better be a bat if you don't carry a flashlight.

15"above my head on the wall behind me sits a THIRTY WATT LED chip being driven at a full 36 volts. THREE THOUSAND REAL HONEST TO PETE LUMENS. Old eyes are like thirty year old plastic headlight lenses - they don't pass light like they did when new. I can not, therefore do not, drive after sunset.

[Gdetrailer]

DrewE wrote:

Gdetrailer wrote:

DrewE wrote:
Fixed link. Tempting gizmo.

If (or when) the $40 lamp on my $10 thrift store 8mm movie projector dies, I might see about cobbling something together based on this or something rather similar. It might even end up being brighter overall.

That little "pea shooter" isn't enough light to get an image to show on a 8mm projector..

I remain somewhat unconvinced that it would not work adequately for my purposes, though obviously it's entirely theoretical rather than practical on my side. I did just, out of curiosity, run a little experiment with a 5W Ikea Jansjö light; it made a quite dim but usable picture at short throw distances. The Jansjö does have the advantage of having a pretty decent optical focusing system already so there isn't too much wasted light out of it.

I'm not trying to light up a drive-in theater or anything like that....

I am not trying to light a "drive in" either, just a small screen area the size of a 8 1/2" x 11" sheet of paper to use a HD camcorder to capture the film correctly.

Under lighting the film causes a lot of digital video noise from your camcorder to show..

The problem is you are essentially trying to get 1000 to 1500 lumens squeezed through an opening of less than 8mm.. Takes a heck of a lot of light to accomplish this feat.. That is why there is a 80W-150W incadescent bulb in most 8mm projectors.

Additionally the incadescent bulbs have a very finely focused reflector behind the filament.. This concentrates a lot of light into that very tiny opening..

I ran into the fact that the "replacement" bulbs now days are junk.. First one I got the filament was so far out of square with the reflector the light missed 90% of the opening.. The result was a bright line at the bottom of the pix and a barely viewable rest of the screen...

The second bulb was better but still was not focused all that well, was a bit dark at the top otherwise useable..

I tried a 20W LED array and only had 50% of the light that I should have..

Tried a 30W array and better but still not as bright as the original bulb..

The 50W array proved to be the closest match and if the projector power supply could have provided a bit more power I would say the 100W LED would be the best choice.

To make a fair comparison for brightness I bought a digital LUX meter and used that to benchmark the brightness..

I also added a lens to the array, this concentrates the light from the array so more light gets through the opening.

I would highly recommend buying a LUX meter, get one that has the sensor separate from the meter readout.. Makes it a snap to remotely get your readings..

[DrewE]

Gdetrailer wrote:

DrewE wrote:
Fixed link. Tempting gizmo.

If (or when) the $40 lamp on my $10 thrift store 8mm movie projector dies, I might see about cobbling something together based on this or something rather similar. It might even end up being brighter overall.

That little "pea shooter" isn't enough light to get an image to show on a 8mm projector..

I remain somewhat unconvinced that it would not work adequately for my purposes, though obviously it's entirely theoretical rather than practical on my side. I did just, out of curiosity, run a little experiment with a 5W Ikea Jansjö light; it made a quite dim but usable picture at short throw distances. The Jansjö does have the advantage of having a pretty decent optical focusing system already so there isn't too much wasted light out of it.

I'm not trying to light up a drive-in theater or anything like that....

[Gdetrailer]

DrewE wrote:
Fixed link. Tempting gizmo.

If (or when) the $40 lamp on my $10 thrift store 8mm movie projector dies, I might see about cobbling something together based on this or something rather similar. It might even end up being brighter overall.

That little "pea shooter" isn't enough light to get an image to show on a 8mm projector..

I used this 50W LED..



From HERE

And that still is not as bright as the original 80W incadenscent light.. And when you get into high power LEDs like the one I showed you BETTER have a massive heatsink and decent fan to keep it cool..

I have to take a few photos of my super 8mm projector LED conversion, pretty cool..

As an additional note, the CRI on these high power LEDS is awful, I found specialized lighting gel filters which are designed for LEDs which get the CRI under control for your eyes.. But cameras are not fooled, have to really play with the white balance..

The big drawback of the LED I used is it needs to see at least 30V DC just to get a glow and to get to full brightness it must have 36V DC..

Mexs version should work on 12V though, I also have a smaller 10W version which does work on 12V, makes about 800 lumens.. Still needs a heatsink though..

[GordonThree]

At that price, those aren't legit Cree leds, they're either counterfeit, production rejects or just plain stolen from the factory (best bet maybe?)

In qty 1000 the "S3" class xp-g2 (highest quality bin, 513lm at 1.5 amps) is $1.44 ea * 4 plus another 25 cents for the mc-pcb plus free shipping... it dont add up!

[westend]

Doesn't the sun shine in Mexico anymore or do y'all need to be under theater grade spotlights at night?
That array is 2000LM. The upside is that it sips power.

FWIW, I just returned from Home Depot, looking for some electrical bits. As I passed by the bulb aisle, there wasn't the usual gaggle of confused consumers trying to figure out which LED bulb was appropriate. HD have widened their selection and prices are falling faster than a prom dress. Good stuff for 120V users.

[DrewE]

Fixed link. Tempting gizmo.

If (or when) the $40 lamp on my $10 thrift store 8mm movie projector dies, I might see about cobbling something together based on this or something rather similar. It might even end up being brighter overall.