sorry - more n00b questions for ya all...
I only found this forum 2 days ago, and it's given me quite a lot of insight into DIY projectors - so much that I want to build one myself (after a dissapointing '100" TV' test that failed miserably).
So, I'm looking to spend a max of around £300, but I'm not sure which way to go - the OHP route, or, custom built projector box...
Which (in everyones opinion) is the cheapest/easiest to do?
Obviously, either way I'll have to dismantle an LCD to get it up and running.
I've read a few bits about lamps/bulb/LED's - just really wanna know which one is best to use (in terms of brightness, cost and lifespan)...was at work today (petrol station) and got the crazy idea of using car Halogen bulbs (not sure how long they last though) - I can get 12v, 60w bulbs for £4.99 - would it be easier and cheaper to just get 'proper' projector bulbs, or should I experiment with the car bulbs?
Stuff I need: obviously and LCD display (if anyone can point me in the right direction here I'd appreciate it - UK links please 😉 ) - something with a good resolution (I'm thinking at least 800*600) which is relativly easy to take apart and install.
Also, lenses - I have 2 condenser lenses that were stolen from an old (1930's) photographic enlarger (they're a bit scratched, but seem to do a good enough job), and I've also got an A4 sized fresnel...can you recommend any decent (and cheap) lenses that I'll need to finish the job off (I don't mind buying from eBay.com - as long as the shipping rate is not too much)
er...anything else that you think I need to think about? Cooling (pretty straight foreward - I'm running an overclocked CPU, so I can handle airflow/cooling no problem)
Thanks in advance to everyone/anyone that replies!
Matt
I only found this forum 2 days ago, and it's given me quite a lot of insight into DIY projectors - so much that I want to build one myself (after a dissapointing '100" TV' test that failed miserably).
So, I'm looking to spend a max of around £300, but I'm not sure which way to go - the OHP route, or, custom built projector box...
Which (in everyones opinion) is the cheapest/easiest to do?
Obviously, either way I'll have to dismantle an LCD to get it up and running.
I've read a few bits about lamps/bulb/LED's - just really wanna know which one is best to use (in terms of brightness, cost and lifespan)...was at work today (petrol station) and got the crazy idea of using car Halogen bulbs (not sure how long they last though) - I can get 12v, 60w bulbs for £4.99 - would it be easier and cheaper to just get 'proper' projector bulbs, or should I experiment with the car bulbs?
Stuff I need: obviously and LCD display (if anyone can point me in the right direction here I'd appreciate it - UK links please 😉 ) - something with a good resolution (I'm thinking at least 800*600) which is relativly easy to take apart and install.
Also, lenses - I have 2 condenser lenses that were stolen from an old (1930's) photographic enlarger (they're a bit scratched, but seem to do a good enough job), and I've also got an A4 sized fresnel...can you recommend any decent (and cheap) lenses that I'll need to finish the job off (I don't mind buying from eBay.com - as long as the shipping rate is not too much)
er...anything else that you think I need to think about? Cooling (pretty straight foreward - I'm running an overclocked CPU, so I can handle airflow/cooling no problem)
Thanks in advance to everyone/anyone that replies!
Matt
I cant answer all your questions, but i'll try to give a few tips:
1) Your light source should be
- small
- bright
- with a near daylight spectrum
2) Your projector should try to bundle the light before it reaches the lcd
3) Any light that is not bundled before it reaches the lcd is lost (it will not make it to the screen)
( bundle(d) light == its direction is known, so it can be bent/directed towards the screen)
4) On average only 5-10% of the light will get to the screen
a 400W halogen will produce 4000-5000 lumen (and those bulbs die after 50-100 hours). There are people that use these lamps for projection. I estimate a car bulb with a lifetime of 100-1000x as long will only produce between 2500-3000 lumen at 400W, so you might get upto 500 lumen out of a 60W car bulb.
Not enough.
Leds and other multiple lightsources:
I haven't heard of any working projects, but feel free to try. Its is not the easy way though.
Metal halide bulbs:
(what I'm using at the moment in my ohp)
Can be had in various shapes/sizes
The small bulbs typically produce 70 lumen/watt, which is pretty good. Life is about 6000-10000 hrs for these.
The color spectrum is excellent.
The bulbs disperse less heat than halogen bulbs.
Disadvantes:
More powerful versions (>150W) are bulky, this increases the difficulty to bundle the light. (Not a major problem when you are building your own box, as you will have to bundle the light anyway, regardless of lamp power. If you use an ohp with a condensor lens you only have to modify it to accept one of the smaller MH bulbs)
HMI bulbs:
Best for projection, very small light source, but expensive and 'only' lasts 400-1000 hours
OHP or build your own box:
OHP = build your own that looks better 🙂
Good luck!
1) Your light source should be
- small
- bright
- with a near daylight spectrum
2) Your projector should try to bundle the light before it reaches the lcd
3) Any light that is not bundled before it reaches the lcd is lost (it will not make it to the screen)
( bundle(d) light == its direction is known, so it can be bent/directed towards the screen)
4) On average only 5-10% of the light will get to the screen
a 400W halogen will produce 4000-5000 lumen (and those bulbs die after 50-100 hours). There are people that use these lamps for projection. I estimate a car bulb with a lifetime of 100-1000x as long will only produce between 2500-3000 lumen at 400W, so you might get upto 500 lumen out of a 60W car bulb.
Not enough.
Leds and other multiple lightsources:
I haven't heard of any working projects, but feel free to try. Its is not the easy way though.
Metal halide bulbs:
(what I'm using at the moment in my ohp)
Can be had in various shapes/sizes
The small bulbs typically produce 70 lumen/watt, which is pretty good. Life is about 6000-10000 hrs for these.
The color spectrum is excellent.
The bulbs disperse less heat than halogen bulbs.
Disadvantes:
More powerful versions (>150W) are bulky, this increases the difficulty to bundle the light. (Not a major problem when you are building your own box, as you will have to bundle the light anyway, regardless of lamp power. If you use an ohp with a condensor lens you only have to modify it to accept one of the smaller MH bulbs)
HMI bulbs:
Best for projection, very small light source, but expensive and 'only' lasts 400-1000 hours
An externally hosted image should be here but it was not working when we last tested it.
OHP or build your own box:
OHP = build your own that looks better 🙂
Good luck!
Noobs are cool!!!
Hey there noobs are cool, how else are we supposed to get good without asking a bunch of questions?
I am also a noob, but I have to say the easiest route is to use a projector panel on top of an overhead projector, but be careful, if you buy a junk panel, you will not be happy, I recommend you look through these forums for panels that work good, and buy locally if you are in Europe(E-bay) otherwise anything shipped overseas, could be damaged, and overheads almost certainly won't make the journey.
also be careful what overhead you buy, sometimes older is better, because you need at least 3000 lumins to project in semi-lit room.
as far as making a box, and designing a projector, if you have time and patience for that more power to you!
I just want to watch movies, and play quake 3.
Take care noob!!
gregory27
cold and grumpy in MN
Hey there noobs are cool, how else are we supposed to get good without asking a bunch of questions?
I am also a noob, but I have to say the easiest route is to use a projector panel on top of an overhead projector, but be careful, if you buy a junk panel, you will not be happy, I recommend you look through these forums for panels that work good, and buy locally if you are in Europe(E-bay) otherwise anything shipped overseas, could be damaged, and overheads almost certainly won't make the journey.
also be careful what overhead you buy, sometimes older is better, because you need at least 3000 lumins to project in semi-lit room.
as far as making a box, and designing a projector, if you have time and patience for that more power to you!
I just want to watch movies, and play quake 3.
Take care noob!!
gregory27
cold and grumpy in MN
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