Instructables

Know of a good light source for a Bat Signal?

I wanted to make a quick and inexpensive Bat Signal for Halloween (to shine on a wall, but clouds would be nice?) and purchased one of those cheap 10 million candle power lamps.  It has the brightness and power, but unfortunately it doesn't have the point-direct light necessary to maintain the cut-out shape; the bright beam has some scattering.  So I thought I would ask if anyone here happened to know of something that would work?  Thanks!

Spunk-Monkey (author) 10 months ago
(Sorry to take so long to respond...) Thanks, I am hoping to get a good projection more than something that looks good as a unit. I have a good strong flashlight that I was hoping to adapt but I have no idea where to find a focusing lens that's 12" or so in diameter. I can find some good tubing though, and I can build another base similar to a Dobsonian telescope. I'll keep looking though. Cheers!
A movie projector light.

Or a simple childes toy projector.

Any light source will do with a focusing lens.

Joe
iceng10 months ago
You need to use a long focal lens about 15 inches

In other words a movie projector.
Batsignal.bmp
mpilchfamily10 months ago
What's more important a spotlight that looks like a cool bat signal or a well project bat signal? Because you can't have both. No matter what light source you use you will have that so called 'scattering' issue. To get a good projection you can't have the shape right up against the light. Also you can't build it to work on all surfaces at any distance from the light. You need to decide what the optimal distance from the light should be for the projection. Then you need to play around with what distance you want to place the shape to get the best projection. Like any projector it has to be focused. In order to make it usable at varying distances the shape need to be able to slide in and out from the light.