Good for a retrofit?

Status
Not open for further replies.
Jump to Latest
M

magajab

Member
Joined 2003
amusingornot.com
#1

Attachments

  • i-1.jpg
    i-1.jpg
    19.4 KB · Views: 385
#6
#10
"I hear the light is a little yellow but is this serious or is there any way round it?" yes halogens are a bit yellow im using a halogen bulb and i dont see any problems but it would PROBABLY be better with a MH setup.

well about the retrofitting thing, the light your talking about would only improve your OHP if its more powerfull then it, and if it lasts longer and so on. and IF u can do it right, u should do more research b4 u rush out and buy it,me im still doing research on "reduced Jacket" Metal halides.

good luck
 
#12
u can buy a hqi system for 129$$$ i been doin some research for a LOONG time and i've found a solution.,, get a bulb from DIYlabs or their partner for 34 + an 85$ ballast from 1000bulbs.com M80 http://people.eecs.ku.edu/~astaples/projector/parts.htm the HQI bulb info said its compatible with ARO and M80 ballasts. and buy 10$ holder from i dont know where...

OK! the bulbs heve BAD color though unlike ROLM'S the color is 3000 which i think is HORRIBLE. and the lumens isnt to great either.well im still doing research on HQI bulbs and REDUCED JACKETS....any info or help on how i can retrofit my OHP would be greatly appreciated.



-Jimmy-
 
#13
These lights can be bought very cheaply in the US. The halogen ones go for about $5 USD (not the kind pictured with the sensor on it).

The fluorescent ones run about $30 USD.

The problem with these lights has always been the degree to which they tend to scatter the light, and deliver it to the LCD as non-parallel rays. Most of the light never makes it out of your projector, but simply bounces around until it is absorbed and converted to heat.

A much better reflector could totally handle this, but there is much disagreement that a good reflector can even be possible for such a large source of light (non-point-source).

Of the "worklight" types, the fluorescent types tend to have a better color temp, and will yield much less IR and UV. They are also MUCH cooler thermally.

If it is possible to build a line-source (as opposed to a point-source) of light by using several of these lamps, you could build a VERY good reflector as a two-dimensional parabolic reclector. It would be "U" shaped, instead of bowl-shaped, but would do for a line-source the exact same thing that a three-dimensional paraboloid does for a point source.

Ain't seen that done yet for a projector, though.
 
#14
Bin there... done that...

I had need for one of these lights anyhow...so I bought one a while ago. Before I mounted it outside the house I played around with it inside my old Elmo OHP. Failure! Allmost no useable light escaped the OHP. I only tried the lamp "as supplied" by the manufacturer, but the results were less than exciting. 🙁


zardoz
 
#16
Now if some bright person out there could build an anti-diffuser...

Imagine some sort of material that is flat on one side, with a million tiny lenses on the other side (or prisms or whatever.

You construct the thing so that any light that hits it from any angle on one side emerges from the other side as only parallel light.

"Messy" (randomly oriented) light IN becomes controlled light OUT.

Then all of these cheap sources would become viable.

It's not impossible in theory.

Any takers?
 
#19
Negative Design said:
u can buy a hqi system for 129$$$ i been doin some research for a LOONG time and i've found a solution.,, get a bulb from DIYlabs or their partner for 34 + an 85$ ballast from 1000bulbs.com M80 http://people.eecs.ku.edu/~astaples/projector/parts.htm the HQI bulb info said its compatible with ARO and M80 ballasts. and buy 10$ holder from i dont know where...

OK! the bulbs heve BAD color though unlike ROLM'S the color is 3000 which i think is HORRIBLE. and the lumens isnt to great either.well im still doing research on HQI bulbs and REDUCED JACKETS....any info or help on how i can retrofit my OHP would be greatly appreciated.



-Jimmy-
Click to expand...


after doing some more searching i've found that there are TWO 250 watt HQI's that are 34$ one is the crappy 3000 color and one is the great 4200 color which makes this a great deal after all... on DIYLABS buy page he doesnt state which bulb he's selling so if you are going to buy it PLEASE buy it from http://yellertwo.tripod.com/yellertwoproducts/id28.html site because you dont know which one hes selling. and i dont mean to deter customers from DIYLABS but there jsut isnt enough info on the bulbs....

and ANOTHER thing, the bulbs say compatible with M80 Ballasts, why doesnt he sell the m80 instead! the M80 should drastically cut down the price! 🙁 seems a lil fishy to me... :mafioso:

if any one decides to purchase thses lights please post it...i'd like to know how it goes.


-V.L-
 
#20
verbose mustafa said:
very few people actually know how to convert candles to lumens... its not as easy as 1 candle = 12 lumens... or what ever that measument is... it does not work.
Click to expand...

(shamelessly stolen from http://dcwi.com/~nybarra/LED.html)

If you want to know the total output in lumens of an LED, you need two things: the candela rating in the beam (2.3 cd in the example) and also the solid angle of the beam. The solid angle is just how much of the surface area of an enclosing unit sphere would be illuminated by the beam. Find the illuminated area in square units, and that number is also the solid angle in steradians. Multiply the candela rating by the steradians to get the lumen output. Of course if you light up the whole unit sphere (surface area of 4 pi square units), then the solid angle is 4 pi steradians, and that's why to convert from spherical candlepower to lumens, you can just multiply by 4 pi.

That's great, but I've never seen a steradian in an LED catalog.
In an LED catalog, if you are lucky enough to find any description of the beam shape at all, it will almost certainly not be the solid angle in steradians, but rather a beam angle in degrees. Since the beam shape is pretty much a simple circular cone, it isn't a problem to convert. Just take the cosine of half the beam angle (be sure you know if your calculator or trig table is working in degrees or radians). Subtract it from 1, then multiply by 2 pi. The result is the solid angle (in steradians, regardless of how your calculator is set). Now you can multiply by the candela rating to get an approximation of the LED's output in lumens. The answer is approximate both because the LED's beam is not exactly the same brightness everywhere within the beam, and also because the beam doesn't really have sharp edges and total darkness around it. But at least you now have something to go on when comparing different LEDs to each other, or comparing an LED to something else you know.
 
Status
Not open for further replies.
Top Bottom