Second try at a projector

I made a low res projector last year, which was a lot of fun researching and building, but when it was done I didn't end up using it much as it weighed way too much it was too bulky and ran REALLY hot.

For my second attempt I had some ideas. This one is going to be a 15” XGA with as high of contrast ratio as I can get. You really notice a low contrast ratio. I am putting this projector in my room about 8’ away from where I want to project and am hoping for a 40”X40” screen as that’s all I have room for. I am going to hook this up to my computer and use the computer as a HTPC.

I was thinking of gutting an OHP and putting a 400w HQI MH and a triplet in it. My question is the OHP Fresnels of high enough quality not to notice any drop in quality? I would build a painted black pyramid from the fresnel to the triplet to trap out stray light.
 

tjh

Member
2004-12-30 5:35 am
RI, USA
If your looking for something neither bulky nor hot I don't know if an OHP is right for you. The only way to optimize everything in the smallest possible space would be folding the light with mirrors in order to make it smaller. And even then with a 400W MH it would run pretty hot.
 
Yea it would be bulky but it would be more vertical and lighter to I can mount it to the roof in my room. I dont agree with mirrors as they can easily degrade quality even with a Front surface mirrow as it has to be exactly at 90 degrees. and I had some ideas for the heat. I was thinking about putting the halide infront of a reflector and then mount it in a large pvc pipe and then cutting a hole with a hole saw in the pipe then cover the hole with pelxiglass and put a fan and both ends and maybe painting the inside of the tube black.
 
Heres the idea I was planning on using.
 

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Sorry I shouldn’t just slam an idea without giving a suggestion. Painting the PVC with black heat proof paint wont protect the plastic. Infact black will make the plastic absorb even more heat. I’m not against plastic, I’m using it in my projector but it has to be isolated from most of the light. Use a metal sleeve to encase the lamp, something like a piece of round metal down-pipe, 20-30mm smaller in diameter than the PVC. You could hold it in position using some wood screws. This would isolate the heat to the metal jacket and allow you fan to remove the heat.

DJ
 

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