The camera and projector are 2 halves of the same artifact. They were shipped to Warehouse 13, and the camera got there, but the projector's delivery lable got torn, so it never reached the Warehouse and became a dead letter, it sat in the Univille post office for 70 years. The reason nobody missed it was because the Warehouse 13 manifest said it had it, but apparantly they haven't done inventory in a while. The projector brought havoc in Univille in S2E03 "Beyond Our Control" because it was being used to play violent movies on TV for a Postman. The movies began projecting and solidifying in town because waves from microwaves and sattelite dishes were somehow messing with the transmission which was why it was projecting all over town. Labelled as item 186 in the Farnsworth Isle, the projector is 186-a and the camera is 186-b.
The camera and projector were both created by Farnsworth for a military operation called Project Gemeni in 1944. The idea was that the enemy would think you were closer, better equipped, and have more soldiers then you really did. However, somehow light became matter and a 3D picture of a sherman tank shelled a crowd of people.
The camera takes a 3D picture of an object then sends it to the projector which was suppose to just create a hologram of that picture. Somehow the artifact developed the ability to make any picture the camera takes and turn it into an actual physical object.