| shipto |
Took a big leap forward today picked up a slide projector from the car boot today for £20 :). I can salvage the lense the fan and the light, Just have to convince my wife to let me spend money on the lcd now :rolleyes:
I think the light may be too little but it should be sufficient until I get a brighter one. |
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| ancorp |
The optics may be too small too, depending on your lcd, I doubt anything more than a 5" lcd will work with those optics.
Consider a triplet. |
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| shipto |
It has a triplet lens says 100mm lense is approx 30-35mm diameter, I tried it with just the light on the wall and got approx 80" screen of light but the light on it was limited by the housing (there is a limited appature for the light to travel through). I am hoping that without the limited appature the picture will be a little bigger but will be happy with 80" or there abouts.
would a 1440 X 234 7" widescreen lcd be ok or is that too low resolution I dont think I can convince wife to let me play with anything more expensive. |
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| dave123 |
| quote: | Originally posted by shipto
It has a triplet lens says 100mm lense is approx 30-35mm diameter,
would a 1440 X 234 7" widescreen lcd be ok or is that too low resolution I dont think I can convince wife to let me play with anything more expensive. |
Not very usable it will almost fit for a 4" psone lcd panel barely, it may even cut the slides slightly.
there are "ways" to make it work but you will loose alot of light and quality. |
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| ancorp |
| my guess is its too big for the lens, but you can try it, get a better lens from an OPAQUE projector. I got a lens identical to that 120$ lens thats 135mm diameter, from an OPAQUE projector, and it cost me $15! (thats with taxes and handling fee too!). That lens may be overkill but it would still work. A triplet with like a 30-35mm diameter will give a pretty dark image from that light source, an lcd takes alteast 70% of the light. If you can find a PS1 lcd, that would be great, because you can use most TV projection lenses (like the Delta 1, 2, 3, 4, etc...) and those lenses are about 75% light efficent, and will give excellent results. |
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| shipto |
| thanks for the advice I will see what I can get with my pocket money :D . If I can get some reasonable results from this I can try to get a better system at a later time. My ultimate aim is to build a complete pc based system but all that can come later. I am a little impatient to get one working for now. |
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| shipto |
Ok got the psone lcd and it is so easy to strip apart (was a little worried after ruining my last lcd). Set up the light and made a mount for the lcd having trouble finding the fresnels though I have one but really need 2nd. I think I may have to invest in a larger triplet lense as suggested but will look around for a better one. Got it all set up (just holding the triplet) and got a picture on the wall but not great. will work on holding the cables secure tomorrow so I can move things around without worrying about breaking them. I thought the heat of the light might cause a problem but the fan seems to be keeping everything cool nicely.
heres hoping for a productive day tomorrow.
cost so far £77 |
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| shipto |
| mounted light, fan and transformer in almost same way as it was in slide projector. |
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| shipto |
made metal bracket for mounting lcd and pcb will weld some sides for stability when I get it all set up properly.
(sorry about the rubbish photo's my camera is way old) |
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| ace3000_1 |
| quote: | | (sorry about the rubbish photo's my camera is way old) |
Try focusing it, then the pics wont be like looking through glases smeard with vasoline.
Trev:) |
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| shipto |
| got carried away and didnt take any photo's until after I had fitted the cardboard template *cowling* and tried it out. I cut the base board to a more pleasing shape. I am thinking about putting some kind of duct from the top of the light to line up with the final casing (I am lucky there work at a place that makes plastic industrial fans so if i take it to work can get one of the guys to weld up a nice plastic case). The cowling before the lcd is lined with silver paper not quite as bright a picture as I had hoped for but maybe with a proper lens? |
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| shipto |
| quote: | Originally posted by ace3000_1
Try focusing it, then the pics wont like looking through glases smeard with vasoline.
Trev:) |
has no focus its a old pac bell dsc3 you cant even take any pics where anyone is moving :apathic: |
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| ace3000_1 |
| quote: | | has no focus its a old pac bell dsc3 you cant even take any pics where anyone is moving |
Digital? |
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| shipto |
| yeah digital heres one I took of the psone dismantled had a little camera shake. these are all resized btw but the origionals dont look any better. |
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| ace3000_1 |
KK, you can ajust the focus then, on the cmos chip you have the lens, if you screw the lens in you can focus the things much closer, however the long distance becomes abit out of focus.
Try to mount the camera on a desk or tripod so it doesnt move when you take the shot, that seems to be your problem more then anything at this stage. If thats no good id ajust the lens.
Keep up the good work, the plastic welding at your work will be a big help when the project becomes finalised.
Trev:) |
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| shipto |
| There I was setting up my projector with my newly made screen and my daughter called me, so I whipped around and knocked the projector over :cannotbe: . Luckily the lcd survived it but the bulb is knackered and I cant find a replacement the bulb is a Atlas c, 24v, 180watt. |
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| shipto |
ok restarted using a 75watt halogen now after obtaining inspiration from Markoh this one is looking small enough to shoehorn into a desktop box which will come in handy when I get hold of the gear to make my media centre. I am planning to seal the box with a fan sucking out of the back and have drilled 15 holes in front of the lcd so the cool air will come into the box as close to the lcd as possible.
Oh yeah I smashed the front lens of the light fitting and put the uv filter out of my slide projector in there I am hoping this wont dull the light too much. |
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| shipto |
I was playing around with the light tonight and it fell face down onto the living room carpet. I didnt notice right away and now have a 50mm burn hole. Wife is not talking to me now :(. I am not having much luck doing this.
On the plus side it works pretty well hooked it up to my camcorder and used a simple magnifying glass held in front I was really impressed with the image once I get a decent triplet it will work great. Will post some pics asap altered it a little from the one above. |
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| HiLLBiLLY |
| Bad luck with the carpet there shipto, damn ...wives just have no sense of humour at times do they?!?@?#!? haha Push on though shipto rome wasn't built in a day and your projector wont be either but when it is it will all be worth it and your wife will care little when shes snuggled up watching her favourite movie with you on a big screen :-) |
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| shipto |
| ok improved the case all sides are held in by 3mm screw except the bottom which is rivetted. Used a aluminium spray to coat it inside and out it seems pretty good, I am even thinking of spraying it lightly on the screen. |
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| shipto |
| Slots on the front fresnel mounting should be good for correcting any keystone which may be useful as I am thinking of a coffee table design if I cant get a triplet to allow me to place it on back wall. |
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| shipto |
| lit up fortunatly the one thing my camera seems to do properly is adjust for bright lighting. |
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| shipto |
finally got my lens for £10 and I am very pleased with it BUT there is terrible light distribution I have tried various glasses in front of the light but it does not seem to help. Had it up and running tonight and I must say with the focus slightly out of perfect the image is great (perfect focus shows the pixels too much) and I think I should be able to get a good image up to about 80" ish maybe a little more.
the further back I am able to go the better ideally I want to throw the image about 10 foot but somehow I dont think its going to happen. |
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| nexarius |
a 75w halogon is much too dim and also has a very 'warm' colour temperature.
You would get better results using a Metal Halide bulb. |
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| shipto |
| I'm kinda thinking that myself I got the inspiration for the 75 watt from http://www.diyaudio.com/forums/show...1154&highlight= but looking again at Markoh's lamp he seems to have a shallower reflector than the one on mine which may be why I cannot get rid of the hot spot. I am going to mess around with a 150 watt halogen (simply because I already have those) and if thats acceptable then I may invest in metal halide. |
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| shipto |
I am having some trouble here I cant seem to get this light distribution sorted out here is a quick drawing of what I have.
I have missed the reflector off this but I have tried with and without at various distances.
I have tried various condensor lenses with no success. Everything I do results in me having a bright center with a dark but still visible outer edge.
I would like to hear some suggestions but unfortunatly will not be able to try anything out because my attempts to correct this resulted in a broken uv glass from getting the light too close. The lcd wont survive very long without it :( |
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| JohnA |
Hey looks like you are off to a good start....Try to keep the wife happy :D I'm doing the same thing http://www.diyaudio.com/forums/show...eadid=44837...I picked up a slide projector and am using a 5" PS One screen. What is different is that my slide projector came with a 300W bulb, unlike the 150 that you guys are talking about....The thing is bright....I pluged it in and almost blinded myself!!!
Good luck! |
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| shipto |
| I will be glad to get this little problem sorted out but am really looking forward to darkening the room pumping the surround and watching LOTR all the way through. |
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| JohnA |
| quote: | Originally posted by shipto
I am having some trouble here I cant seem to get this light distribution sorted out here is a quick drawing of what I have.
I have missed the reflector off this but I have tried with and without at various distances.
I have tried various condensor lenses with no success. Everything I do results in me having a bright center with a dark but still visible outer edge.
I would like to hear some suggestions but unfortunatly will not be able to try anything out because my attempts to correct this resulted in a broken uv glass from getting the light too close. The lcd wont survive very long without it :( |
Being a newbe I don't know much either, but have you tried a condesor lens between the light and the first fresnel...? |
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| shipto |
| yes I have tried various lenses I have lying around but Have just thought of something I have the lenses out of the origional slide projector but i cut up the holders for my first try which dropped. I will try over the weekend to get them arranged the as they where in the beginning maybe that will solve it? Just need to find another bit of uv glass now which should be easy enough to get hold of. |
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| Guy Grotke |
Maybe you should try removing the LCD panel and the upper fresnel. Then put a sheet of white paper where the LCD panel would go. Look at the light on the paper: Is it uniform? Does it have the same width and height as your lower fresnel? This setup lets you adjust the lamp, condensor, etc. until you get it right.
Then remove the paper and put the LCD and the upper fresnel back in. Move the paper between the upper fresnel and the projector lens. Does the light converge into the lens? If not, maybe you can adjust the upper fresnel until it does. Once that is done, you will have to adjust the projector lens to focus the image. You might have to adjust one, then the other, a few times to get it focussed with all the light hitting the lens.
If the light engine is adjusted correctly but it still looks bad, maybe your projector lens just does not have a wide enough angle... You could try a big magnifying glass projecting a 15" image to see if it looks more uniform.
You could almost double your light output, by adding a spherical reflector. A dichroic one would be the best, since it would not reflect the IR, but I don't know where you can get one. Once you do get the lamp adjusted, you could try an experiment with a soup ladle, a mixing bowl, or anything reflective with a true spherical shape. Avoid a parabolic or flat reflector: Those don't help for this application. |
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| shipto |
ok played around with it tonight and I think I have solved it I had the light too close which is a bit of a shame because it is I was hoping to cut it down but hey its going to work.
I think the main thing to help me get it set up right will be to make the object lens a permanent housing which I can do tomorrow if I have the right size tank cutter in my kit.
After that I really need to get the uv glass I only tested it for 10 minutes tonight before the screen started to blacken where it was running for hours before. |
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