specially cut box, green file folder, and manila folder
small 3 finger clamp
telescope clamp and wood block
Set up as shown with the box between projector and lab jack and screen supported by the 3 finger clamp just above the box. To block stray light, place the green file folder as shown and the manila folder “tented” over the top of the projector.
Remove the lens from the projector. Turn off the lights in the room and turn on the projector lamp.
Adjust the height of the lab jack until a slit of light goes through under the edge of the box.