Don't do it. You can get a lens to put in front of the projector to change the output size. I don't know where to get them, but I have seen them in use on home theaters
A couple of lags into studs on the triangle part is all you really need. You can put some drywall anchors on the star part if that makes you feel better about it.
2muchtimewastedhere t1_ixzv9h3 wrote
Reply to Removing part of a floor joist to embed a projector. by mejelic
Don't do it. You can get a lens to put in front of the projector to change the output size. I don't know where to get them, but I have seen them in use on home theaters