greetings
i've been a sponge on this thred for a couple weeks now and decided it's time to add my 2 cents. first off, I encourage anyone who hasnt't alredy done the OHP/projection panel setup to give it a try. i got my setup about 3 weeks ago for about $130 total and it works better than I ever expected.
I recommend trying to find the stuff locally, as the shipping charges on ebay tend to jack the price of larger(OHP) items beyond their real value. There are always companies selling off their old obsolete crap in the paper. I got my OHP for 50 bucks from a guy who bought out an A/V company. Keep in mind that to most people, these items are of little use, and don't let on that you're using it for something really cool. You could probably score a lot of them and sell them to readers of this thread.
So, you ask, where's the DIY? I fully intend to adapt/ modify/ improve my setup, but in the meantime iI have a working projector which I can disasseble quickly, use parts from, modify, etc... and if my ideas don't work, I just put it back together and I still have a pretty decent 80" image on the wall.
BTW.. MY first project used a headlamp from a car; good quality light, but couldn't get the light bulb out of the projected image
i've been a sponge on this thred for a couple weeks now and decided it's time to add my 2 cents. first off, I encourage anyone who hasnt't alredy done the OHP/projection panel setup to give it a try. i got my setup about 3 weeks ago for about $130 total and it works better than I ever expected.
I recommend trying to find the stuff locally, as the shipping charges on ebay tend to jack the price of larger(OHP) items beyond their real value. There are always companies selling off their old obsolete crap in the paper. I got my OHP for 50 bucks from a guy who bought out an A/V company. Keep in mind that to most people, these items are of little use, and don't let on that you're using it for something really cool. You could probably score a lot of them and sell them to readers of this thread.
So, you ask, where's the DIY? I fully intend to adapt/ modify/ improve my setup, but in the meantime iI have a working projector which I can disasseble quickly, use parts from, modify, etc... and if my ideas don't work, I just put it back together and I still have a pretty decent 80" image on the wall.
BTW.. MY first project used a headlamp from a car; good quality light, but couldn't get the light bulb out of the projected image
the lcd projector I got has more problems than just a need for a new bulb. In fact, the bulb even works (FXL). Powers up but the bulb wont come up.Well, took a look at the parts and everything seems to be in fairly good condition but a fuse that is dark in the middle (hehe, burned?). Going to need to send it to someone to replace as the damn fuse is kind of glued or too tight and I cant even read the fuse type. Should be very cheap to fix.
Anyway, took a look at the parts and like I expected, nothing much on it. The projector has 2 boards. One for the inputs and the other for the power and stuff.
Optics is pretty simple and makes me really wonder why we cant really get awesome quality from our DIY projectors.
Ill try to draw later but here it goes.
1. lamp: there is a small part for the FXL lamps. Three are two on it and the projector figures it out itself when one is not working and automatically switches.
2. lens. Three is a small lens right on front of the bulb. it is a bit bigger than the bulb. So I guess we are making a mistake trying to make a reflector as big as the LCD panel. I think it should be as big as the condensor. Didnt measure but looks like it is about 3 to 4"
3. Mirror: About 6" ahead there is a mirror. The mirror is in on side of a orthogonal black box. This box looks like those from the 100" TV some people make.
4. LCD: There is a huge LCD in there right in the middle of the projector. It's about 8"
5. Mirror: another mirror in there. This one directs against the bulb but on the other side
6. Projector lens. three is an adjustable lens in there. Cant say for sure but it looks like a triplet or at least doublet lens.
xx: fans: three is one huge vertical fan right besides the bulb and one computer case type fan on the bottom right in front of the LCD. the huge one takes the heat out.
Thats about it.
so may plans now are:
1. find a small MH or mercury or xenon bulb
2. create a parabolic reflector for this bulb
3. buy two mirrors at about the size of the LCD width (8.4")
4. Find a quality condenser a bit bigger than the reflector diameter
5. buy a quality field lens.
To create the reflector and buy the mirrors should be very cheap. I already have a "testing" 640x480 LCD pnel (but will later upgrade for a 1024x768 one) and computer case fan. I only need to invest some money on the bulb, find a good fan for the bulb and condenser/field lens.
Ill NOT to use fresnel lens from the OHP as i have planned before.
k boys, time to start spending money!!!!
well, cant edit anymore so here is the corrections.
there is a fresnel right before the LCD. Couldnt see that as it was "hided" into that orthogonal box.
So, I assume they used a pre-condenser and them a fresnel. So, here it comes me using the fresnel again hehe
so now my question is: althoug i knew some projectors use pre-condenser, what is its real function? to me it looks like it makes a lot easier for building the reflector as it would only have to be as big as the pre-condenser.
I might be wrong.
well, the fuse is burn and Ill have to find a way to fix it. (very bad position for the fuse and it is somehow "glued". Therefore I cant see the lights coming through,but im sure it goes now that i corrected my post
If the problem is only the fuse, Ill have this projector for the bedroom and the one ill build for the living room, if not i at least can use its optics. and since its LCD is as big as mine Id be set with the optics. Id just need to add better bulb. (MH)
there is a fresnel right before the LCD. Couldnt see that as it was "hided" into that orthogonal box.
So, I assume they used a pre-condenser and them a fresnel. So, here it comes me using the fresnel again hehe
so now my question is: althoug i knew some projectors use pre-condenser, what is its real function? to me it looks like it makes a lot easier for building the reflector as it would only have to be as big as the pre-condenser.
I might be wrong.
well, the fuse is burn and Ill have to find a way to fix it. (very bad position for the fuse and it is somehow "glued". Therefore I cant see the lights coming through,but im sure it goes now that i corrected my post
If the problem is only the fuse, Ill have this projector for the bedroom and the one ill build for the living room, if not i at least can use its optics. and since its LCD is as big as mine Id be set with the optics. Id just need to add better bulb. (MH)
Marklar,
short focal lenght = image larger
long focal lenght = image smaller
icculus,
i think it's a good point to start with a working setup like OHP+projection panel. You can go the way back if some adventures are not succesfull ! If someone builts a projector from the scratch and doesn't exactly know what he's doing, this can quickly end up in a waste of time and money, especially if he hasn't a clue, how optics work!
xblocker
short focal lenght = image larger
long focal lenght = image smaller
icculus,
i think it's a good point to start with a working setup like OHP+projection panel. You can go the way back if some adventures are not succesfull ! If someone builts a projector from the scratch and doesn't exactly know what he's doing, this can quickly end up in a waste of time and money, especially if he hasn't a clue, how optics work!
xblocker
just fixed that projector. $3 on a new fuse and professional service and the "beauty" is working.
Note:
1. Not much difference of quality from the OHP/panel setup.
I was wondering if I could replace its lcd module for a higher quality one (for that the pins to connect to a controllet board must be the same) and on the small part for the lamp if I can manage to do something in there and use MH instead of that low life/lumens halogen lamp (FXL)
I will probably remove the lamps, place a mirror on it and build an outside lamp housing.
That could be a nice "DIY LCD projector upgrade" project hehe
Note:
1. Not much difference of quality from the OHP/panel setup.
I was wondering if I could replace its lcd module for a higher quality one (for that the pins to connect to a controllet board must be the same) and on the small part for the lamp if I can manage to do something in there and use MH instead of that low life/lumens halogen lamp (FXL)
I will probably remove the lamps, place a mirror on it and build an outside lamp housing.
That could be a nice "DIY LCD projector upgrade" project hehe
Parabolic mirror?
I found several posts about parabolic mirrors, but they all talk about using them to focus a light source. Has anyone thought about using one after the LCD? OK, the basic problem is that you can see an LCD with a normal backlight just fine, but when you try to put that through a lens smaller than the LCD, the light sneaks around the edge of the lens so the resulting projection is dim. How about catching all the light from the LCD with a parabolic mirror of the same size as the LCD and then focusing that on the lens? This way much more of the light that gets through the LCD actually gets to the projection lens. You can use those LEDs as your backlight now. Should I draw a picture?
I found several posts about parabolic mirrors, but they all talk about using them to focus a light source. Has anyone thought about using one after the LCD? OK, the basic problem is that you can see an LCD with a normal backlight just fine, but when you try to put that through a lens smaller than the LCD, the light sneaks around the edge of the lens so the resulting projection is dim. How about catching all the light from the LCD with a parabolic mirror of the same size as the LCD and then focusing that on the lens? This way much more of the light that gets through the LCD actually gets to the projection lens. You can use those LEDs as your backlight now. Should I draw a picture?
Question
For those of you with OHP's, would you consider the fresnels to be of greater, lesser, or the same quality when compared to a typical page magnifier (Office Depot variety)?
After closer inspection, and an image wash-out problem that couldn't be cured, I realized that my "new" OHP has a very worn-out fresnel. I think someone used an abrasive cleaner on it! I didn't realize this until I compared its clarity to the edges, where I assume the cleaner missed. It is acting more like a diffuser than concentrating lens system.
So, I am thinking about using two page-magnifier fresnels, back-to-back, when I construct the enclosure for the projector. I know it is less than optimum, but so is my current situation. I have e-mailed Inventory Solutions about buying a salvaged fresnel, but I haven't heard back from them.
I am also dealing with Macrovision problems in a BIG way. Nearly any DVD I place in my Toshiba SD-3750 produces the bright/dark pulsing every 10 seconds or so. Not watchable. I guess I'll have to get one of those stabilizers.
Hey dwalls32! Welcome back to the board.
Zeco,
Congrats on getting the projector running. Would replacing the panel AND the circuit be possible? I know that my panel has easily removable/movable components and would be suitable for a retofit job. Unfortunately, it is only 640x480 (nView Spectra C). It might be difficult to find a discrete panel that would be an upgrade AND be compatible with the existing circuit. Good luck.
-f4
For those of you with OHP's, would you consider the fresnels to be of greater, lesser, or the same quality when compared to a typical page magnifier (Office Depot variety)?
After closer inspection, and an image wash-out problem that couldn't be cured, I realized that my "new" OHP has a very worn-out fresnel. I think someone used an abrasive cleaner on it! I didn't realize this until I compared its clarity to the edges, where I assume the cleaner missed. It is acting more like a diffuser than concentrating lens system.
So, I am thinking about using two page-magnifier fresnels, back-to-back, when I construct the enclosure for the projector. I know it is less than optimum, but so is my current situation. I have e-mailed Inventory Solutions about buying a salvaged fresnel, but I haven't heard back from them.
I am also dealing with Macrovision problems in a BIG way. Nearly any DVD I place in my Toshiba SD-3750 produces the bright/dark pulsing every 10 seconds or so. Not watchable. I guess I'll have to get one of those stabilizers.
Hey dwalls32! Welcome back to the board.
Zeco,
Congrats on getting the projector running. Would replacing the panel AND the circuit be possible? I know that my panel has easily removable/movable components and would be suitable for a retofit job. Unfortunately, it is only 640x480 (nView Spectra C). It might be difficult to find a discrete panel that would be an upgrade AND be compatible with the existing circuit. Good luck.
-f4
sharp image
After 8 month since I started this project, mostly I learned, tested and tuned optical thing, because I think optical is the crusial part of the projector and I won't go to the next step before I get the perfect result.
The main problem is: I couldn't focus the whole projected image evenly, when I got sharp in the middle, the outer perimeter was blur, vice-versa.
I think all of this problem called Abberation.
First is Spherical Abberation (For lenses made with spherical surfaces, rays which are parallel to the optic axis but at different distances from the optic axis fail to converge to the same point.), so far I know, to eliminate this problem is:
1. using double convex lens.
2. covering 1/3 to 1/2 of the outer edges of the lens.
3. using two identical lens to perform as single lens.
Second is Chromatic Abberation (a lens will not focus different colors in exactly the same place because the focal length depends on refraction and the index of refraction for blue light (short wavelengths) is larger than that of red light (long wavelengths).), how to eliminate this problem?
-. using achromatic doublet or triplet lens.
Am I right about all of this? Are you facing the same optical problem as mine?
Please tell me how's your projected image look-like,is it sharp evenly? no blur at the edge of the image?
No blue and red shift on the projected image color?
What's kind of lens you're using?
BTW, I'm sorry for water cooling idea, I'm not the first, I did the drawing for my setup and share it with all of you, but if you search "water" on the printable version, you will come up with a long discussion about it.
see you.
After 8 month since I started this project, mostly I learned, tested and tuned optical thing, because I think optical is the crusial part of the projector and I won't go to the next step before I get the perfect result.
The main problem is: I couldn't focus the whole projected image evenly, when I got sharp in the middle, the outer perimeter was blur, vice-versa.
I think all of this problem called Abberation.
First is Spherical Abberation (For lenses made with spherical surfaces, rays which are parallel to the optic axis but at different distances from the optic axis fail to converge to the same point.), so far I know, to eliminate this problem is:
1. using double convex lens.
2. covering 1/3 to 1/2 of the outer edges of the lens.
3. using two identical lens to perform as single lens.
Second is Chromatic Abberation (a lens will not focus different colors in exactly the same place because the focal length depends on refraction and the index of refraction for blue light (short wavelengths) is larger than that of red light (long wavelengths).), how to eliminate this problem?
-. using achromatic doublet or triplet lens.
Am I right about all of this? Are you facing the same optical problem as mine?
Please tell me how's your projected image look-like,is it sharp evenly? no blur at the edge of the image?
No blue and red shift on the projected image color?
What's kind of lens you're using?
BTW, I'm sorry for water cooling idea, I'm not the first, I did the drawing for my setup and share it with all of you, but if you search "water" on the printable version, you will come up with a long discussion about it.
see you.
Re: Question
Possible if I build the whole thing by myself (as I planned) and take all of the great optics out from it.
Thing is: For my bedroom, this commercial projector is GREAT. Unless I could replace the module for a higher quality one, Id rather not mess with it. If I could, them Id mess on changing the light source as well and make it to work on the living room.
My bedroom is about 12" and the projector works great for that. It produces about 75" 4:3 screen.
My living room is huge. Its about 40". Enough room to fill the whole wall (8ft tall) and build a huge screen. however, it is not suitable to do it using a 640x480 panel as the pixels are clear visible (unless I rearrange the living room so I can sit a lot further from the screen).
Here are the parts I have so far:
1. A commercial Boxlight 2100 projector.
2. a 640x480 (800x600 compressed) LCD panel from polaroid
3. a Buhl 211 overhead project.
both OHP and projector use FXL halogen lamps.
what can I do for the living room? Well, I can take the OHP mirror, fresnel and doublet lens out of it. Build a lamp housing and find a 1024x768 panel on ebay.
Result: I sell my 640x480 panel and buy a 1024x768 panel.
[b]fender4[/b] said:
Possible if I build the whole thing by myself (as I planned) and take all of the great optics out from it.
Thing is: For my bedroom, this commercial projector is GREAT. Unless I could replace the module for a higher quality one, Id rather not mess with it. If I could, them Id mess on changing the light source as well and make it to work on the living room.
My bedroom is about 12" and the projector works great for that. It produces about 75" 4:3 screen.
My living room is huge. Its about 40". Enough room to fill the whole wall (8ft tall) and build a huge screen. however, it is not suitable to do it using a 640x480 panel as the pixels are clear visible (unless I rearrange the living room so I can sit a lot further from the screen).
Here are the parts I have so far:
1. A commercial Boxlight 2100 projector.
2. a 640x480 (800x600 compressed) LCD panel from polaroid
3. a Buhl 211 overhead project.
both OHP and projector use FXL halogen lamps.
what can I do for the living room? Well, I can take the OHP mirror, fresnel and doublet lens out of it. Build a lamp housing and find a 1024x768 panel on ebay.
Result: I sell my 640x480 panel and buy a 1024x768 panel.
Re: I need luck
it's 1024x768. i started bidding on it. i see you've jumped in on the bid also. damn...heh
prjctr_builder said:i have found an LCD panel on ebay.com that supports 1280x900something resolution. if i win it and get a dukane OHP, my image is going to RULE, wish me luck!!!!
aleksey
it's 1024x768. i started bidding on it. i see you've jumped in on the bid also. damn...heh
Fender4:
I don't know what your home theater situation is, but with mine, I have a Surround Reveiver setup for the sound. Of course, this has a video switch built in, and when I hook the DVD player up to the receiver, macrovison is no more. This is because the receiver has like 4 video inputs and one out to the tv(plus vcr rec loop), so there must be circuitry to counter act macrovison built in, but the movie companies probably dont want them to announce this. If I hook up the dvd player to the vcr, there are problems. But put the receiver in the middle, no prob, and the receiver even has a vcr record loop, 2nd vid out, which also does not suffer from macrovision.
I don't know what your home theater situation is, but with mine, I have a Surround Reveiver setup for the sound. Of course, this has a video switch built in, and when I hook the DVD player up to the receiver, macrovison is no more. This is because the receiver has like 4 video inputs and one out to the tv(plus vcr rec loop), so there must be circuitry to counter act macrovison built in, but the movie companies probably dont want them to announce this. If I hook up the dvd player to the vcr, there are problems. But put the receiver in the middle, no prob, and the receiver even has a vcr record loop, 2nd vid out, which also does not suffer from macrovision.
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