Go Back   Physics Help Forum > High School and Pre-University Physics Help > Light and Optics

Light and Optics Light and Optics Physics Help Forum

LinkBack Thread Tools Display Modes
Old Sep 12th 2017, 01:13 AM   #1
Junior Member
Join Date: Sep 2017
Posts: 2
Cheap / simple homemade projector

Iím trying to build a relatively cheap and easy projector based on a Cree flashlight. Iíve experimented with cut outs, homemade slides, etc., and am pretty well convinced Iíll need to add a lease or two to make it viable.

Iím hoping to project a relatively large image from say 30 feet away, at night. Probably on the side of a building or on the ground from
A high point.

I eventually want to be able to replicate this cheaply and share instructions for others to do so, but would be thrilled to at least get a prototype going from which I can learn and improve it.

Can anyone help me figure out lenses, distance, etc. - the setup for this?

Thanks so much.
OpticalNoob is offline   Reply With Quote
Old Sep 12th 2017, 05:01 PM   #2
Senior Member
Join Date: Apr 2017
Posts: 271
Cree flashlights are a great innovation very powerful , energy efficient many power outputs , and cheap ... I expect you have one ...switchit on and focus it so it gives the narrowest beam ...

Aimed at a wall two meters away the light is seen as a squarish shape with grid lines on it , about 20 cm square ....

This is the first issue , the light source , the led , is not a point , but a square shape about a mm in dimension ........I would imagine if you put a slide in front of the torch you would not be able to get a sharply focused image projected on a screen ...

Have you tried that???

There are no extra lenses required , nothing that will help get a better image .
IDEALLY The torch is projecting a cone of light that originates from a point .
But because our source is not a point , blurring occurs ...all you can do to reduce this, is have the slide as far away as possible from the torch.

Last edited by oz93666; Sep 12th 2017 at 05:28 PM.
oz93666 is offline   Reply With Quote

  Physics Help Forum > High School and Pre-University Physics Help > Light and Optics

cheap, homemade, projector, simple

Thread Tools
Display Modes

Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
emye cheap authentic jordans online jqxuo hlhmtcmu Advanced Mechanics 0 May 18th 2016 04:57 PM
How to build a short throw projector for a photography studio xseven Light and Optics 3 Jun 6th 2014 11:52 AM

Facebook Twitter Google+ RSS Feed