I've interfaced an Arduino to an 8mm film projector and a DSLR to convert films to video. I'll be describing the various parts of the project and also working on moving it into a soundproof enclosure.
I've made the following components on the projector:
* The original bulb is replaced by a high-intensity white LED. It's throwing the light only a few inches into the camera sensor so we don't need the same power as before.
* The original AC motor is disconnected and I connected a cordless drill motor onto the shaft. The motor is driven by an H bridge under PWM control from the Arduino.
* An IR sensor is connected to detect the rotation of the shutter blades.
Additionally the Arduino drives a relay to control the camera shutter.
The Arduino itself is controlled by a linux PC running a simple script to cycle through the 4,500 frames of the standard 3.5min film. The camera takes 3 pictures of varying exposures for each frame. Then the 13,500 frames are assembled into a video.