The Bauer projectors with DC motor, like the T502, T525, T600 and the T610, use a rather simple motor driver print. The speed is not really accurate (16 and 24 Hz=pictures/second). But when you want to digitize films, speed must be exact.
There are two possible solutions for digitizing films.
- Using a Video camera. When a video camera is used then the projector must follow the speed of the camera. To be able to do this the Vsync signal from the Video camera can be send to the projector which should synchronize is some way to this signal.
- Using a Photo Camera. When a photo camera is used, the projector must send a (trigger)signal to the camera, when to take a picture. So, here the photo camera must follow the speed of the projector.
Some designs has been made in the past to be able to synchronize a projector with the Vsync signal of a video camera and hall sensors have been used to generate trigger signals for a photo camera.
I have created an all-in-one solution that is able to work with both a video and a photo camera. It can also set the speed of the projector to some fixed values like 16, 20 and 24Hz. But the speed can also be set with steps of 0.1 Hz between 16 and 24Hz. Synchronization for a video camera is possible by using a direct Vsync signal or by a CVBS video signal. The new motor-board just fits on the location of the old motor-board. To measure the actual speed of the projector the small tacho-board is replaced by a new one, that does not have a lamp, but uses small LEDs. The dashboard lamp, still an old fashioned lamp is replaced by a LED lamp, which can be controlled in intensity. A small box with display and 4 buttons is used as a user interface. Settings can be made with this user interface. It can show the speed of the projector and has an image counter just as the T610, when the projector is running forward or backward.
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