What really makes this prop stand out is the animation that happens when Dalton presses the button. This isn’t just a stationary projected image, but rather an animation of a portal opening. To pull this off, he crammed an entire projector into his portal gun. However, it got a little complicated when he began trying to trigger the animation.

I wasn’t able to directly control the projector without making a menu pop up in the projection and that spoiled the effect, so I opted to use an LCD shutter borrowed from some 3D glasses to obstruct the projection. The projection of the portal is a rotating flash animation that is converted to MP4 format so it will play nice with the projector. The projector can store videos on a microSD card so I just set it to loop the portal animation and sound effects. When the shutter is blacked out, power is removed from the Adafruit mono audio amp that is connected to the headphone jack on the projector. With no audio or projection the portal gun appears to be idle but the animation is always running.

Apparently, inside this portal gun, the animation of the portal opening is happening forever, in an endless cycle (this sounds like a plot to one of the shows!). You only see it when Dalton presses the button, which opens the “shutter.”

But how does Dalton know when to hit the button? Wouldn’t he end up opening the shutter in the middle of the animation most of the time? Some clever fiber optics help with that.