these are 2 videos made from scanning the same 100 feet of 16mm clear leader. The first, Greenhouse Fans and Dissimilar frequencies was made before I was able to match the frames per second on the projector to the rate of capture on the camera I was using. The second, When you look back between your knees your glasses touch your eyebrows, was made once I devised a way to perfectly synchronize the projector and the camera.

Greenhouse Fans and Dissimilar Frequencies

When you look back, between your knees, your glasses touch your eyebrows

More on the hardware (plus some backstory (like when you need to scroll forever before you get to a recipe online)):
About a year ago I was in the market for a 16mm film projector. I work as a film projectionist, I have worked in a 16mm film archive, and I wanted to be able to watch some of the 16mm film prints I have at home. I found a Bell and Howell Filmosound for $40 on Ebay… the seller thought it was an 8mm film projector. Once it arrived, aside from some dust and caked on emulsion, it was in good shape and it ran surprisingly well. I would use it every now and then and it was fun, but flash forward 6 months and I moved into a new apartment and every time I tried to start up the motor, the breaker for that circuit would pop. This is how I learned that 1. the motor likely had some kind of short in the windings causing it to draw more than 20amps, and 2. the breakers in my old apartment we’re likely faulty because they never once popped.
After feeling sad for a day, I found the silver lining: not only can I now justify buying a new 16mm film projector, but I also have the opportunity to give a projector->scanner conversion a shot. The electrical component of the projector were, as far as I could tell, shot; but the mechanical components of the drive still worked perfectly. My plan was to gut everything I don’t need (AC motor, amplifier circuitry, relays, lamp components, blowers, etc.) and use cheap a PWM controlled hi-torque DC motor and a simple LED lightbulb to drive and illuminate the projector. This was much simpler than I anticipated, and once I designed a 3D-printed adapter for the dc motor to fit in place of the larger ac motor, the rest was pretty straight forward. Well, at least that part was relatively straight forward. I still had to devise a system to focus the film plane onto my digital camera, and a system for automating the shutter.

For focusing, my goal was to avoid buying a new lens. I have a collection of inexpensive but high quality SLR photo lenses. The plan was to find one that, when paired with a reasonably sized extension tube, magnified the film to cover most of the full frame sensor. The winning combination was a 55mm Pentax lens, reverse mounted with a 110mm extension tube, and with a 3d printed adapter so it can be focused using the preexisting projection lens focus knob.

The last hurdle was finding a way to automate the shutter on the digital camera. My original idea was to use a built in shutter automation that takes a picture every ‘x’ seconds, but matching that timing to the timing of the DC motor proved to be impossible. There would be a few frames captured perfectly, but because of the timing mismatch the blades of the projector’s shutter would slowly creep up or down depending on if the camera was leading or lagging. My next idea was to use some kind of switch or button that would be pressed by some mechanical component in the drive system, closing the circuit on a remote shutter button and taking a picture. The problem here was that I couldn’t find a reasonable place to put a switch where it would be easy to time it so that the shutter was out of the way. In the end, I used a photo resistor and a raspberry pi to make a very simple circuit that could tell when the shutter is out of the way of the film, and control a remote shutter to take a picture with the digital camera. I was daunted by including a micro-controller, but it was actually very simple to set up with a small solder board and a little bit of python. I’ve tested it at around 1 frame per second because thats the fastest my motor can drive the projector, but I plan on putting a slightly faster motor in and seeing if I can get closer to 2 or more frames per second.