Conventional Fixtures Students Building a Leko Light

[McCheese]

I have a group of 13-year old students that are going to be building scale LEKO lights. These will be scale models of the real lights. While they are smaller versions, the students are hoping to build these with the basic functionality of the real leko lights. They have been researching the basic design, but have had some difficulty finding truly detailed plans / spec drawings, so there will be some definite trial and error.

I am looking for advice / ideas on types of materials, etc as well as maybe some websites that could be helpful. We do have the plano-convex lenses and a couple of different lamps to try, but not sure of the distance from the elliptical to the gate, etc. I would alos welcome other suggestions for materials.

We are on a pretty limited budget, and I do not have much of a technical background when it comes to lighting, so I'm learning along side the students as we go.

Any thoughts would be welcomed! Thank you!

 

[Robert]

Mini mag lights have an elliptical lens and a focus feature. Tear one of those apart maybe?

 

[McCheese]

Thanks. That is one of our light sources that we are going to be trying. We actually have a couple of smaller flashlights that may fall victim to this project.

 

[Les]

You could also try an MR-11 or MR-16 lamp. Just be aware that you'd need a little space for the socket and you need to have a transformer of the correct voltage (12v is pretty common). Some of those smaller MR lamps can be battery operated.

 

[tjrobb]

I would avoid MR11, MR16 would be better. We have down lights with 11's in them and are finding the lamps incredibly difficult to source. You may have more luck in your area, though.

 

[kicknargel]

If you know the shape of the elliptical reflector, you can find the focal point or gate.

 

[MNicolai]

Before building a housing or the heavier bulk of these models, I'd suggest getting some lenses, and a light source and fixing them to an adjustable track. The track would be probably 2' long, and then you could have the light source and reflector at the end of the track, and then use the track to adjust the distance the lenses are from the lamp. If you wanted to experiment with gobos or irises, you could do that too by adding them onto the track between the lenses and the light source.

The whole thing may be a little advanced for a group of 13-year olds, but there's a lot of fun to be had in this style of physics experiment. Learning how different lenses work at different distances gives an enormous amount of insight into how light and lenses behave.

After you dial the lenses in and determine the best distance for having them from the light source, you could model the housing around those dimensions.

 

[chausman]

Before building a housing or the heavier bulk of these models, I'd suggest getting some lenses, and a light source and fixing them to an adjustable track. The track would be probably 2' long, and then you could have the light source and reflector at the end of the track, and then use the track to adjust the distance the lenses are from the lamp. If you wanted to experiment with gobos or irises, you could do that too by adding them onto the track between the lenses and the light source.

That actually sounds like a really fun project. Where would you start trying to find lenses?

 

[MNicolai]

If you've got the money, you can buy ETC, Strand, or any other company's lenses from a lighting dealer.

If you don't, you can call up some local theatres or rental shops and ask them what old lighting instruments they have floating around. Usually anyone with a lighting inventory that's older than 10 years has accumulated a pile of instruments that are useful only for being cannibalized for their parts. Generally these get turned into worklights or will be used as a last resort on a show when there's nothing else to use, but they're perfectly fine for science experiments too.

The ellipsoidal isn't a new piece of technology. They've been around for more than a few years now and if you call around I'm sure you can dig some relics up that nobody will mind if you steal the lenses from.

For that matter, you can do the same experiment with fresnel lenses too, or if you want a really crazy experiment, take a look at what ETC uses in their PARnels. The optics of a PARnel are really quite astonishing. Think about it -- what optical properties do two lenses need to perform a flood to spot adjustment by only rotating one of the lenses?

 

[Joshualangman]

The Isbrytare light from Ikea is a great mini ellipsoidal-like fixture that comes with a bunch of parts you could use — mini lenses, shutter unit, iris unit, gels, gobos, and rods on which to move everything back and forth. It seems like they're no longer selling it, but you could find some somewhere.

Found some info:

http://qhib.blogspot.com/2005/08/isbrytare-spotlight-from-ikea.html

It's essentially a Source Four Mini, just really cheap.