DIY Video Projector

[wnichol]

Two quick questions.

What direction should the fresnel be when its before the lcd?

What projection lense would anyone recomend for my final projection lense (I'm using a 4" lcd)?

[fender4]

Hey, I just found out a way to search this thread (since the search on DIYaudio doesn't do much good for searching within a thread). At the bottom of the page, there is a "Show Printable Version" link that will take you to a page with all of the posts show at once! Then you can use the Ctrl-F or Find function to search for keywords, topics, parts, etc. Maybe everybody already knew that, but I sure didn't. It would have save me a good bit of time seraching for things. Hope this helps.


wnichols,

For you purpose, I would recommend the Fujinon lens from Surplus Shed. According to the description, it will accomodate a source up to 4.25", so you may be in business. I have one, and it does seem to be a hih quality item. Good luck with it.


-f4

[contrapasta]

It may be just me, but I'm not understanding jjasniew's problem with the vg140, with the last picture it shows the panel with the circuit boards completly out of the way of everything... Am I missing something... Which connecter is the problem?

So anyways, jjiasniew (or anyone) have you solved the problem, is the vg140 board workable for our needs?

[contrapasta]

And is this the connecter your referring to that should go here?? Did you try to email them to see if they would sell overseas??

[gav]

ever since i began reading this board and looking at the ovation lcd monitors on ebay, the prices seem to be going up and up...are we all bidding against each other??? what seems to be a reasonable price to pay for a 820?

[Scot_lad]

Just to mop up a wee question: OHPs have a much smaller lens than the size of the image source, because the light beams converge towards the smaller lens. This is achieved because of the fresnel arrangement between the light source and the LCD panel.

As for image 'speed', sorry I've not idea at all what that means, XBlocker, maybe you could explain for the non-US guys?

I am looking forward to watching my latest DVD on some kind of projection system: does anyone remember Jamie and the Magic Torch?

www.80snostalgia.com will provide a nice distraction from projector panels and lenses...

[Grumpy_Git]

Scot_lad

I asume that by speed, Xblocker is refering to the aperture of the lens, allowing more light through and thus (for a camera system) allowing a shorter or faster exposure.

As For Jamie and the magic torch, I never really liked it, Will 'o' the wisp was more fun.

Nick.

I've no money at the moment, grrrrrr. Experimenting over...

[lokost]

fender4

Try reversing the Fujinon lens. Normally you have to place the object very close to it to project a good image; I have observed that by reversing the lens you can increase the object distance and therefore easily cover a much bigger object. The wide angle attribute of the lens is still preserved.

[fender4]

Thanks or the tip, lokost. I've tried it, and unfortunately, I am still missing about 30% of the image. I have ordered a plano-convex lens that has a focal length of ~12" (the same one that Gunawan recommended), so hopefully I can use that to "gather" the image and send it to the Fujinon. I think I am being limited by the short focal length of the Fujinon.
-f4

[jjasniew]

You have outlined the problem precisely. I have not yet checked them out, to see if they'd mail overseas.

In your second photo, the connector is just underneath the edge of the PCB where your arrow points. I believe their solution will work; it's just a matter of getting it.