Friday, October 7, 2011

LED Projector Mark II

After completing my first led projector mod i was commissioned to do another one, with an even more powerful led this time

This time around i modified a phillips hopper sv10, which had a burned out polarizer i replaced earlier in the year. Thinking the interface would be identical because of the same manufacturer and they were similar models built around the wrong time, obviously i was wrong.

Instead of a heart beat signal and active low feedback the control signal was a simple active high pulse, feedback required a constant 5 volt line to be pulled down. Using my scope wasn't very helpful as i was expecting a squarewave signal (really need a second probe while im at it) but my new logic probe made quick sense of it.

This time around i used a 50 watt led, 32 - 36 volt power supply, reflector and a pack of credit card frenel lenses to play with.

I mounted the led exactly the same way as before: i removed the uhp bulb cage and hacked off a piece that screwed onto the rest of the assembly

Drilled small pilot holes for mounting the led

Then drilled and tapped for 6 - 32 screws

The plastic piece i hacked off was bolted to the top to mount the led at the perfect position.

 A bit of thermal silicone to hold the led in place and give better thermal conductivity

And finally screw into place. My control board is nearly identical to my previous version, with the exception of the extra transistor used to pull the 5 volt line to ground

Alot smaller and cleaner than my last version, also i found a place to pull 5 volts off the power supply removing the need for its own supply.

Im still in the process of testing different lenses but the credit card frenel lenses seem to do the trick... im a bit concerned that it might sag during prololged operation since it is just a piece of cheap plastic.
Time will tell i suppose, perhaps adding a fan to blow over the front of the led is a solution.

So far it is quite a bit brighter than the 25 watt led i previously used, but it does get much hotter and i will need to attach a fan directly to the heatsink i used, seems to get close to 45c right now but that is with the case open

I am unable to take proper pictures of the projector in action, everything i take with it is way to dim to make out most of the projected image

Nearing the completion of the project i had an accident: i dropped a screw while reassembling the projector which just had to hit a 400v 150uf capacitor which discharged onto the control interface cable and destroyed it... The projector survived, could turn on and off and would display fine through vga but i could not change any settings or inputs making the projector quite useless.

I guess its off ward to the next one, an eiko EIP-2500 DLP projector... i plan on taking the led system from the now failed mod and installing it into the dlp projector


  1. Wonderful! following this quite closely as I'm trying to do this with a Philips SV2

  2. Would much appreciated if you ever got a chance to post some schema of the board including the components. Thanx!

  3. i don't have any schematics of the projector itself, but i can draw up one for the lighting controller i built

    the projector should use a similar interface, i took a look at the dlp projector ill be modding and the hv supply is built into the rest of the power supply... which will require more poking around than the previous versions

  4. Schematics for the controller would be quite helpful indeed and much appreciated. Speaking on behalf of a huge community of Eletro enthusiast out there in Europe/US, thank you for undertaking these various projects!

  5. Great post. Thanks.

    I've practiced using the scope, and can easily measure constant wave forms. This weekend I will have a go at looking at the control signal for my Fujitsu.


  6. ive been really busy with midterms recently, ill have some free time coming up this week so ill do up a proper schematic and provide source code

  7. Been looking to LED mod a Benq DLP. Can you recommend a suitable LED pls. What are you thoughts on this 6 Cree LED module?


  8. i would try to match the rated lumen output of the original projector as closely as possible

    for dlp projectors, typically what i have seen from dismantling them is that the window where light enters for the mems assembly is quite small, so you could be able to use a smaller led array

    you might even be able to use on of these powerful emitters:

  9. What was the projected image like on this mod? Any photos?

  10. Not many photos unfortunately, the camera i had at the time gave terrible washed out blurry photos because of the extreme contrast of a dark room and the projected image

    my first mod was dimmer than the original bulb but with the 50 watt emitter my last (failed) mod was a near perfect replacement, very bright and even lighting the led managed to work flawlessly, unfortunately burning out the control panel i wasn't able to adjust color and brightness to see how well it worked.

    my concern with dlp projectors is the small window where the light enters, the one i have is only a square centimeter, roughly the size of an sst90 emitter, hopefully the emitter does not produce a hot spot in the image, otherwise some sort of diffuser would have to be used which would result in a loss of light output