However, I did some fiddling with color wheels later on, at another job of mine. You can either set the color wheel aside (mine were just taped to a plastic box on the side of the projector) and use its’ pulse to drive the DLP chip, or you can do what I did later and just make an Arduino send similar pulses. If you use an RTC you can keep the drift really low.

Interestingly, you can freeze some DLP projectors on single frames and look at the dithering done for each color. Watch out, some projectors do not use a signal directly off the color wheel, rather they have a photodiode down the optical path that reads to a sensor mounted directly on the mainboard.

But for a solution you can use now… IIRC the TI DLP development kits have grayscale capability and they have come way down in price. Check out the DLP commander series. Though more expensive than commercially available projectors, they save a hell of a lot of development time. I can’t say much about what I did with them, but they’re good to work with and a lot more fun than fooling around with commercial stuff and all the attendant problems.

Feel free to contact me if you need more info. I’d love to know your application.

Further, if you fully remove the colorwheel (unplug it) so you can close the projector, will the system still work, even though it does not get the positional feedback from the colorwheel?

Thanks
Chuck

Marian Petrovici
Iasi, Romania