Hello everyone,

I am new to the forum. I am interested to use a laser instead of lamp to send an image to DMD chip. I have bought an old Infocus X1a with no lamp. I have rigged the lamp door micro-switch so the projector thinks that the door is closed. I want to fool the projector to think that the lamp is connected but somehow it knows that the lamp can't be ignited. Do you know how the projector senses that the lamp doesn't ignite? How to fool the projector to bypass the lamp test and send the video image to the DMD chip?

Infocus X1a is using TI's DDP2000 ASIC series. I can't find the data sheet for this chipset to investigate about how the controller knows about the lamp's health.

Projector message: The projector comes up with blinking green LED (once after each try). After 5 or 7 tries, it comes with red LED blinking.

Thanks,

hjavadi

I think the issue is less of it can't ignite, and more of it knows there is no bulb in the lamp ;) I would try to buy a burned out lamp and shove it in there, see what happens then. If that STILL doesn't work I would say it has some kind of current/resistance monitoring going on.

You'll have to alter some of the circuitry in the lamps ballast, which senses if the lamp is good when it trys to ignite, then i believe, as stated above, it will keep a watch on the current/flow.
However, the question is, will you be able to get powerful enough lasers and be able to disassemble the color wheel system and then get the lasers to fire at accurate and fast rates? Not to mention, will the above mentioned laser be bright enough?

Thanks for your replies.
To answer the questions from jarrod1937: as the laser is monochrome (HeNe 630 nm red), and I am interested in black and white images, the color wheel doesn't have any use for me but it can be left alone; I don't plan to remove the color wheel.
Intensity of laser is another story and I will find out how well the micro-mirrors reflect the laser. My laser is 7 mW out of the HeNe. First I need to fool the projector though.

Thanks for your replies.
To answer the questions from jarrod1937: as the laser is monochrome (HeNe 630 nm red), and I am interested in black and white images, the color wheel doesn't have any use for me but it can be left alone; I don't plan to remove the color wheel.
Intensity of laser is another story and I will find out how well the micro-mirrors reflect the laser. My laser is 7 mW out of the HeNe. First I need to fool the projector though.
Oh ok, didn't know you were going for a monochromatic image.

How will you get the laser light to cover the entire DMD and not just a few mirrors in the center?

How will you get the laser light to cover the entire DMD and not just a few mirrors in the center?
You can use optics to spread the light. A similar thing is done in some lcd projectors i've repaired, where a lense spreads the light out right before it hits the first polarizer and then the panel.

You can use optics to spread the light. A similar thing is done in some lcd projectors i've repaired, where a lense spreads the light out right before it hits the first polarizer and then the panel.

Yes, I was aware of that. Since he was asking us for details, I was asking him for details. He will need to use some very specific calculations and I was hoping to see some of that math...

Yes, I was aware of that. Since he was asking us for details, I was asking him for details. He will need to use some very specific calculations and I was hoping to see some of that math...
Oh i see, well, maybe we'll get some math still :-) My answer was not specific, still plenty of room for him to tell us the specifics.

Don't spread laser light. Lasers are for scanning. Fresnel lenses are often used to even out light distribution even with traditional bulbs, especially with LCDs. No reason to use a laser over an LED if you're going to try and illuminate it all at once. And you'll run into the same problem - you need too much room for LEDs to give the brightness you need. A laser is essentially a condensed LED light source, so spreading it back out seems to have no point.

Actually LEDs are replacing halogen lighting now and will take less room than the cage used in your PJ now.

Bulb manufacturers Osram (Osram Opto Semiconductors) have updated the Ostar Lighting LED - creating an LED spotlight bulb which is brighter than a 50 Watt halogen spot light with a lighting output in excess of 1,000 Lumens of cold white light.

The new improved hexagonal Ostar Lighting LED uses around 22 Watts of electricity to generate 1,100 lumens (at 50 lumens per Watt) with a current of 1 Amp. This is a fraction of the consumption of an equivalent ~100 Watt incandescent bulb or 50-60 Watt halogen bulb but considerably more than many other less bright LED spotlight bulbs.

In order to get 1,100 lumens out of the Ostar six 1 square millimeter LED lighting chips had to be packed tightly in the unit using the latest high density chip-packing techniques. The fitted 38 degree reflector lens increases the light output by around 30-40% without changing the beam characteristics.

The Ostar Lighting LED should last 10 times longer than an equivalent halogen spot bulb, and 50 times longer than an incandescent lightbulb with an average life time predicted of 50,000 hours.

When PJ manufacturers actually decide to use it is a different story.

...
The Ostar Lighting LED should last 10 times longer than an equivalent halogen spot bulb, and 50 times longer than an incandescent lightbulb with an average life time predicted of 50,000 hours.[/I]

When PJ manufacturers actually decide to use it is a different story.

I wonder what the spectrum is like...
Colour rendering can be a bit of soft area for LEDs.
si.

I wonder what the spectrum is like...
Colour rendering can be a bit of soft area for LEDs.
si.They have seem to have figured that out, you can get 2800k, 4200k, 4500k, 6000k, 7000k or daylight so I don't think color is going to be an issue.

...No reason to use a laser over an LED if you're going to try and illuminate it all at once. And you'll run into the same problem - you need too much room for LEDs to give the brightness you need. A laser is essentially a condensed LED light source, so spreading it back out seems to have no point.

Laser light is also coherent and of a very narrow spectrum compared to LED light. Gives it some unique applications.

The Ostar Lighting LED should last 10 times longer than an equivalent halogen spot bulb, and 50 times longer than an incandescent lightbulb with an average life time predicted of 50,000 hours.[/I]



Ever seen a high power LED? They use pretty large heatsinks.

GO to the Osram website and check out this Ostar led setup. It looks much different than previous led configurations.

Oh i see, well, maybe we'll get some math still :-) My answer was not specific, still plenty of room for him to tell us the specifics.

Hi jarrod1937 and reconlabtech:

Sorry to left you cold without showing some calculations. I am using a melles-Griot x3 beam expander to go from 1 mm beam diameter to 3 mm. To cover the whole DMD chip, I can make my own optics: first I will use a high N/A lens to transfer the collimated beam into a point source and then recollimate using a big diameter lens.

Don't expect any deep math from me yet as I take my task one at the time. If you are into use of lasers you can read the articles by academic researchers who use DMD for 3-D imaging systems (mostly reported in SPIE conferences).

I have to learn how a ballast works before attempting to fool it. Can you share with me how the power supply senses the lamp current in Infocus X1a projector?

Thanks,

hjavadi

Lasers don't use ballasts.

Lasers don't use ballasts.
We're talking about bypassing the lamps ballast to allow the projector to function without the need for the lamp. The ballast, which keeps the current flow study usually will report a dead lamp if no current is sensed.
However, hjavadi, i do not know the specifics of the x1's ballast to help you out.

I really feel stupid in taking your time before doing my homework. I serached for "ballast" and "sense" and got a wealth of information. Such as two below:

LC

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Posted on Thursday, March 18, 2004 - 9:01 pm:

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If you guys are still interested to bypass the lamp circuit for infocus projectors, here might be some useful information...

There should be two electronics boards, one is the DLP and video signal control, the other one is the power supply. The two boards are connectted via a connector.. which is probably 12 to 18 pins. That connector has the usual voltage supplies, such as 5, 12, -9, gnd connections. THere are also two very important pins on that connector that interlocks the lamp control.. One pin, signal comming from the digital board to the power supply, tells the power supply to ignite and keep the lamp on. If this pin is 5 V, the power supply keeps the lamp on.

The other pin is the feedback from the power supply to the electronics. When the lamp is happy, this pin is at 3.0 to 3.3 volts.


So.. all you need to do... is short the feedback pin to 3.3 V supply on the power header. That way, the electronics will presume that the lamp is all happy, and the rest of the electronics will be running just fine.

THis way, you can do away with the big resisters and heat sinks. The lamp can be completely removed and the projector will run just fine.



RAGEdemon

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Posted on Thursday, November 20, 2003 - 7:32 pm:

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Projectors (or any such device such a video recorder etc) do not come with instructions such as these as 1) a person is not expected to utilise the equipment at that depth, 2) they do not want you to mess with their components at that depth.

Never the less, i have managed to determine the needed infrmation and successfully attempt a bypass.

I have used 2x 100W 33-Ohm resistors, bringing the total up to 66-Ohms, 60W dissipated in each. The heat is quite extreme thus i have had to attatch 3degreesC/W heat sink's to each.

It works perfectly, though i can not say it will work for you. The high current in the lamp makes it very dangerous to work with - be careful!

Total price, £10 + 10 for heat sinks. £25 for 12000Lumen mercury lamp with 6000hour life. Total: ~£50 + £25 every few years for replacement lamp.

If yo decide to buy from manufacturer, £300+ every few months.

On a side note, if you still plan to buy a bulb; open up the bulb abd read the markings. Chances are, you ill be able to get the bulb far cheaper from another supplier than the manufacturer's model.

From where it is assepbled i could get my lamp for £180 whereas for the same lamp the manufacturers and distributers were asking for £475+

Wish everybody the best of luck, if anybody needs any help with lamps, you know where to ask :-)

As stated by John above, Common sense, and BE CAREFULL!

-- RAGEdemon

Anyway sorry for the distraction. I will post on my experience when trying to use a laser.

hjavadi

We're talking about bypassing the lamps ballast to allow the projector to function without the need for the lamp. The ballast, which keeps the current flow study usually will report a dead lamp if no current is sensed.
However, hjavadi, i do not know the specifics of the x1's ballast to help you out.

You'd have to remove it. Ballasts are high voltage drivers.

I really feel stupid in taking your time before doing my homework. I serached for "ballast" and "sense" and got a wealth of information.
[B]Anyway sorry for the distraction. I will post on my experience when trying to use a laser.

hjavadi

No need to apologize! Thanks for posting this. I remember seeing this kind of info before on a diy site but forgot where. I'm glad you are making progress. Please keep us informed, I'd like to know how it turns out for you.

:)

You'd have to remove it. Ballasts are high voltage drivers.
Some ballast are computerized and may have to be altered, not just removed. You may be thinking of the simple ballasts, but they can get quite complex, and depending on their use, be complexly integrated into other circuitry.

Hey, I'm not saying it's a good idea to begin with. Because IMO, it's not.

Maybe not for DIY, but here's a peek at laser future:
http://www.avsforum.com/avs-vb/showthread.php?t=946331

I like the idea of lasers when professionally implemented. The whole point of this thread is about implementing a laser incorrectly (by widening the beam instead of scanning) and it's too much work for a consumer.

I like the idea of lasers when professionally implemented. The whole point of this thread is about implementing a laser incorrectly (by widening the beam instead of scanning) and it's too much work for a consumer.
You're missing the point, its for the fun of doing it :)
Sometimes diy stuff is just for fun not practicality.

In my application, I am interested in finding the laser beam distortion by the optical system and therefore I need to use one coherent laser beam to illuminate the whole aperture. Scanning the beam doesn't work for me. Sorry.

hjavadi