LCD Overhead Projector

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Comments

[Derin]

Would the Liesegang trainer portable T work?It shines from above and replaces the clunky frame with a slim mirror.

[Coggz]

Hey, I've got a slim ohp here that shines the bulb down and mirrors it back up. Would it work the same? I got the ohp for £20 and it would be great as it is slim. It is this projector: http://www.vega.si/eng/?template=product&art=9 I hope this works as it would be the cheapest projector ever...
Luke

[add.thebad]

would it be possible to do a similar thing but use a high power garden lamp and mirrors because i don't have a ohp

[waterppk]

The overhead projector does a few things the garden lamp doesn't. The mirror at 45* angle in the overhead projector base the bounces the light through the LCD actually passes the infrared light through it (making the other instructable having you add a IR Filter not necessary). The optics on the "head" of the ohp actually project the image, if you passed it through the garden lamp you'll be much more dependent on the distance and geometry from the screen you're projecting on. The reason that ohp bulbs are special is that they give off light in a broader "flatter" spectrum, meaning the light coming out of them is balanced and won't discolor the images, if you're a huge movie/display buff you'll likely hate the results, if you're just looking for a big screen to watch movies on and don't really care the difference in spectrum isn't the end of the world.

That said, there isn't any reason you can't do this, you can add an IR filter (or just have more cooling capability), and you can place it an appropriate distance from whatever you're projecting to.

[add.thebad]

would it be possible to do a similar thing but use a high power garden lamp and mirrors because i don't have a ohp

[adin99]

hey waterppk my name is adin and im attempting to build one of these projectors from your guide. I have gotten to the step that requires me to extend the LVDS cable. Thanks to your comment to ongissim i was able to find the extension cable on digikey. Now i have the cables but am wondering where to go from here... What type of wire do i need to use to connect the parts, and how exactly do i do this, hey thanks a lot in advance -Adin PS please respond here or email me at [e-mail] Thanks!

[ongissim]

I have the same problem with the FPC cable being in the way of the screen. However, when I search Digikey, I can find the connectors, but not the 16 pin cable. What was the model number of your cable? Also, was your pin pitch .5mm?

[waterppk]

My pitch was .5mm, I was only able to get a 20 pin cable, which i trimmed the 4 pins off the side and carefully align it whenever I need to unplug/plug it back in. It's been working well.

You can find them in the DigiKey PDF catalog, but I wasn't able to find them online through their search. Download the catalog section A and scroll to page 85, on the left hand column you should find .5mm pitch cables in fixed lengths (max 8 inches).

If you have to search the cables are called -
0.5mm Pitch Standard Length Jumper Unshielded Flat Flex Cable

PM me if you need any more help with anything.

[adin99]

hey waterppk my name is adin and im attempting to build one of these projectors from your guide. I have gotten to the step that requires me to extend the LVDS cable. Thanks to your comment to ongissim i was able to find the extension cable on digikey. Now i have the cables but am wondering where to go from here... What type of wire do i need to use to connect the parts, and how exactly do i do this, hey thanks a lot in advance -Adin PS please respond here or email me at [e-mail] Thanks!

[ursula_c]

i tried to make one, but the lcd screen wont stay on. it flickers on and off, anyone know how to fix this problem?

[lardbob]

I made one and it works perfectly, apart from a white line of dead pixels down the screen because one of the screen address cables got damaged :( Nice instructable!

[jcdj]

cant you just replace the bulb in the projector with a worklamp light bulb, it would get much brighter, right

[waterppk]

You can replace the bulb in the projector with something else, but it probably wouldn't be any brighter.

The reason for using projector bulbs is that they are typically quite bright but most importantly color balanced and focused. If you were to stick a work light halogen bulb or something in the projector you'd be dumping half of the light in the wrong direction, would get bright/dark spots on the screen and the color balance would be wrong because the light spectrum would be shifted. (That's a comparison between LED's and CCFL's but you get the idea). Another potentially dangerous problem is improper cooling, halogen bulbs typically have more IR output than projector bulbs and may not adequately be cooled by the normal fan.

[jcdj]

ohhh, ok i uderstand what your saying, i was asking cause im gonna use my lcdprojector for a multi touch computer screen,

http://www.instructables.com/id/Back-projection-56-inch-multitouch-television./

i dont want to use a worklamp bulb if it has more IR output then a projector bulb, because it would mess with what the multi touch input, is their a brigther bulb i can get because i want a really crisp picture....

[xeniczone]

You could take a shot with Metal Halide, they will put out around 20,000 lumens and will be close to white light which is 5000K. Either way you need to take a IR filter and put on the front of them. Because if you use a Worklight you are putting yourself at risk with the amount of IR that comes of them. Worklight will put you at risk of getting sun burn without the IR glass filter. I think the same is for the Metal Halide.

[barrywilliams]

Just to clarify . . . There is no real exposure risk from the infra red (IR) from the lamps. The real hazard is ultra violet (UV). Metal halide and halogen both have integrated UV filters. The real problem with these high-output lamps is the IR can damage the LCD. Overhead projectors have a filter in them and they use a dichroic mirror that allows the IR to pass through the back and reflects the rest. If you've been to the dentist you've seen a dichroic mirror.

[alsyan]

can i use 3m the five "o" eighty eight to build a LCD video projector thank's

[waterppk]

I don't see why not, looks like a smaller/more portable version of a typical projector. Good Luck!

[jeoncs]

Just a random thought but would a portable DVD Player LCD be able to do this as well? That would be cheaper and nice for a stand alone unit without the computer.

[delliott87]

a. i bought a RCA to VGA adapter cable thinking i could run it from the cable box to the monitor but now i see (a little lower on the comments) that probably won't work...what would you suggest to run my cable rca output to the monitor? b. i cannot figure out what to do about the ffc cable...what do you suggest? it seems like i could solder directly to the board on one side but the other one has a connecter the cable used to slide into. any thoughts?

[waterppk]

Don't really have a good solution to the RCA video problem, there are converter boxes you can buy but then you're getting close to the cost of a real projector. You can remove the connector and solder directly to the board, that's what I ended up doing on the laptop projector, otherwise you can purchase another flat flex cable and connector. Take the new FFC and connect it to the connector on the board, then put the new connector on the end so that you can solder the new extension wire to the connector pins.

[bogaloids]

hey this is a great project.. just wanna ask if you can send me a wiring or schematic diagram of this so that i can easily construct mine.. thanks alot!!

[waterppk]

There isn't much for a wiring diagram, basically the only change is just to rewire pin to pin a longer cable in place of the stock flat flex cable. There are no changes to the overall wiring otherwise. The only other change to the monitor is just to simply disconnect the inverter powering the CCFLs or to unplug the CCFLs and electrical tape over the high voltage connections.

[nursgon]

will this cable work? I have all the parts just trying to figure out how to get the movie to the LCD screen. I thought if I hooked this cable to the LCD then ran a RCA video from my DVD player it would work.

[xeniczone]

No, That cable is just an adapter, it is made for a projector or a LCD screen that already has the converter built in. It won't just work on any LCD screen.

[nursgon]

Got the cable and it don't work you need a converter to change video single to VGA or use a LCD screen that was made to go from monitor or TV. my brother sent me a LCD flat screen with both hook ups on the monitor, I will try to build with it.

[waterppk]

I've never used one of these but if they're advertising it as going directly from RCA input to VGA Output then it should work fine. The only issue I can see is that the timing signals and video formatting may not be correct for the monitor, so you may get video but it might look terrible. . . Let us know if you decide to buy one and if it works!

[animefanatic]

would it be at all possible to use a CRT monitor... I have a bunch of them and do not know what to use them on.

[waterppk]

There are CRT projectors but they work differently from CRT monitors. About the coolest project for CRT monitors is to tear them apart, harvest anything cool off of the boards (not much) and then us the flyback transformer that powers the tube to carefully and safely build a Jacobs Ladder/Forks

[djlaurenx]

Im confused... what are we hooking up to the monitor in order to play movies or dvds? This part is confusing and seems to be not clarified in this or your other projector instructable... Am I hooking up a dvd player to this? and where? or to another computer? via what port???? THANKS

[waterppk]

Typically all computers are equipped with DVD drives, so you can just put the DVD in the computer and play it from there. I usually use VLC Media Player for video playback on my computer.

If you wanted to hook up something with an analog input to your computer you can purchase a PCI video capture card or a USB video capture device.

You could also use a LCD TV which comes equipped with inputs and a TV tuner already in the monitor, rather than a LCD computer monitor. There are some LCD monitors with component/composite/RCA video inputs as well but that's not a typical feature.

[djlaurenx]

Sweet, thanks for the prompt response. I have an LCD monitor on a dinosaur laptop, so it has no dvd drive :( ... just trying to figure out an alternate method to do this as there are tons of 10.00 overhead projectors for sale in my area right now! lol

[waterppk]

Great to hear on the projectors and please post what you figure out for a bulb. One thing you might want to look into is a full sized box projector, lumenlabs sells kits but you could piece your own together, this would not require the use of an overhead which it sounds like you're shooting for.

The only reason real projectors use the expensive lights is primarily due to color balance (having true "white" light), even lighting across the screen, and obviously brightness. There are lots of bulbs out there and many will work, you'll just end up with some of the above conditions not being met as well as a "real" bulb.

[snarblarg528]

Hi I was wondering how much screen resolution mattered. I've seen a few dirt-cheap 12-13" LCD monitors on eBay but their max resolution is 800x600, and then I've also seen some cheaper 14" or so which run at a 1024x768 res. Are these "good enough" for wall projection, or are very high-res monitors much preferable?

[melsoftm]

higher the resolution the better !! =) good luck !

[waterppk]

To compare to LCD TV's, the best you can buy is a 1080x set [x = (P)rogressive scan or (I)nterlaced depending on selection], otherwise you can get a 720x or 480x. These numbers are the vertical resolution of the tv, so expensive tv's are:

1920 × 1080 (1080x)
1280 x 720 (720x)
640 x 480 (480x)

So if you get a monitor that is 1024x768 you'll have more resolution than a top of the line TV right now.

The resolution deal aside, I would try to get a screen that fits on the projector, try to avoid one that hangs off the sides as it gets annoying not having the right/left inch of screen.

[waterppk]

the hyperlink isn't suppose to be there, it's suppose to say:
{ x = (P)rogressive scan or (I)nterlaced depending on selection}

but the hyperlink thing got me because I used ['s

[melsoftm]

Hey this is an awesome Idea! I had a spare lcd screen and found a projector for 25 dollars on craigslist, the setup worked perfectly, but then my projector system failed, I looked further into and it seemed that my system had browned out! I saw that others have posted that their setup had browned out but their descriptions didn't fit how my system failed, so I took the multimeter to it =P, found out that there wasn't enough load on the circuit so my chip set fried =(, the back light was the load that was missing from the whole setup =(, I was planing to use the lead to power my fans to cool the screen, but unfortunately my setup died before I could =(, looking for another screen now! I love this idea!

[Dhetshi]

What if I use a 9 inch LCD will it have good picture and resolution. Answer my question to [e-mail] Thank you

[Self-Serving Martyr]

How much do the replacement bulbs for the overhead projectors usually run?