Only G/B projector question.

[JasonB]

+1 What epyn said. Nice note on the unity gain epyn!
Whiteg, a TL082 Op-amp would be a nice choice for your color summer. Google TL082 for the pin-out.
Be sure to let us know if you have any questions or issues.

-Jason

[epyn]

Haha that's funny since both are hungarians.I gave advise in english to my compatriot...I am dumb@ss.

[buffo]

Building a summing circuit is NOT the way to do this.

As both Wookieboy and Swamidog posted above, the way to do this is in SOFTWARE. That way if you add a red laser in the future, it's a simple software switch to support full RGB, vs having to re-wire the projector.

Adam

[whiteg]

Yes I collecting money for red module. (There are only a few months)