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View Full Version : Anyone Tried This?



ak49er
10-03-2007, 12:54 PM
I was at the waste transfer station the other day, and a fellow was throwing away a beat up old rear projection T.V. After some chat, he helped me to set it aside. I returned later with my tool kit and removed the screens and mirror. When I got home I took a knife and seperated the outer "diffuser" screen from what apperars to be a "Fresnel" like sheet that was on the inside. Today I am building a frame to hold the "fresnel" lens sheet in front of my 'pit. The plan is to set the projector to beam forward from my pit, bounce of the old T.V. mirror and reflect the image to the back of the Fresnel lens. This should allow me to look through the image rather than at the image, adding depth. I beleive this is similar to a collimated display system? I have seen systems where they do this and project to a screen as well, so the viewer would actually be looking through the screen at an image as well as at the projected image. I can tell already that just the lens alone won't be a large enough image for my needs. I'm still holding out for a three beamer set-up. This might be better for a smaller GA style pit or an enclosed fighter type motion pit. Additionally, I now have three projectors, they are all different types and resolutions. Will I be able to use them with a Matrox Triple head? And does the newer matrox have analog as well as digital outs? Has anyone experimented with this Fresnel lens type of visuals and if so any suggestions, comments?

Bob Reed
10-03-2007, 01:09 PM
I think PaulEMB has done something similar... We will have to wait and see what he says...

pylet
10-03-2007, 05:22 PM
Here's a copy of my post from the "Hot spot Gone" thread.
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I tried something a little radical this weekend. I took the screens out of a 65" DLP big screen TV and cut them down to fit my windscreen... about 42"x32". This totally encloses my cockpit now. I then have my overhead projector hitting a mirror in front of me and reflecting back onto the "new" cockpit windows. Here is a small video YouTube - Testing New Cockpit Wind Screen showing a couple of take offs and landings with the test windscreen. In the video it appears to have a major hot spot but I don't see that from the cockpit. Not sure why the camera picks that up. Also, the stuttering is the recording web cam. You can see that even I stutter in the video as well to prove that it's the cam and not the display frame rate. Biggest bitch is that the display is a little fuzzy out toward the outer edges, not sure why or how to correct.

Anyway, I have not seen anyone trying to make cockpit windows out of old big screen tv screens so I thought I'd try it.

PaulEMB
10-04-2007, 02:41 AM
I have two side screens that use a 32" fresnel lenses in front of 17" monitors.
These are mounted in black painted boxes, with a depth of around 30".
Whilse these don't fill the size of the side windows, they give a very good immersion factor, as you can only see the side view - coupled with matrox on the front it works fairly well.

I did experiment with a front view, but the quality of the lenses leads to some distorsion, and whilst it was better than a just a monitor, it was still disappointing.

Check out the collimated displays over at projectmagenta for some ideas - I had long discussions with Enrico some time back, and the general view is that this type of display is good, but requires precise positioning of the point of view to get focus - move your head over to one side, and you lose focus, an effect I also get with the side views.

If you watch a back projector TV you get a similar effect - you have to sit with a fairly tight area to get a good view.

I would say it is worth experimenting - we all have different ideas, and this type of display will also be affected by the room you sim is in and ambient lighting conditions. One of the reasons I didn't like it is because I have glass on two sides of the garage/porch where the sim is, and although I use curtains, there is still a lot of light (Ok except at night;))