Film Projectors

Hallo alle zusammen,

As a mechanical engineer, I am interested in how mechanisms work. After few years in school I started to look at things like I didn't see before. I find myself asking some questions, how does it work, why is that knuckle used etc. It is valid even for a toy.

One of the mechanisms I find interessting is film projectors. How a camera takes a picture, I get that. But filming one, to combine bunch of frames without our eyes noticing, that is what I admire the most. 

I love watching movies. I can count so many reasons. When I go to a cinema, before the movie start, I like to hear that projectors working noise like 'trrrrrrr'. I prefer to sit at backside of hall and not just because the view is better to see, it is also to hear that sound. It gives me a little excitement about the movie, a little joy. With that I can notice the difference between watching a movie on my laptop and watching it at cinema. But popcorn is a plus too, of course.

Here is a video about how the mechanism works,

It seems a very old clip, it's almost like it was taken right after the projectors invention. But the jobs of the parts are elucidated clearly. Film projectors consists of 4 main parts. These are the wheels to storage, the lenses to focus the light, the lamps to transmit the frame to the screen and the audio system to us can hear. 

Apart from the video,

As you see above, there are two slacks on film. The first one, above the gate, is for allowing the shutter proceeds to the next frame without tearing the film. The second one, under the gate, is for the photosensor can sense certain amount of light at a given time to transform it into current so that after current can be transformed to voices, as we hear from speakers. You may ask why there is a distance between these two slacks. The distance ensures that the picture and the sound synced perfectly. The distance is about 26 frames.

Another fascinating thing is that the whole system is driven by single motor.

Here is all I know about film projectors. Hope you like it. 

Bis bald!