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Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 mm Film


Like many people, [Emily] discovered herself on COVID-19 lockdown over the summer season. To benefit from her time in isolation, she put in combination an (*4*)optical audio decoder for previous 16 mm movie, constructed the use of fashionable parts and a little of 3-D printing.

It all began with a damaged 16 mm projector that [Emily] were given from a chum. After repairing and checking out the projector with a roll of movie purchased at a flea marketplace, she found out that the movie contained an audio observe that her projector couldn’t play. The audio observe is encoded as a translucent strip with various width, and when a masks with a slim slit is positioned excessive it modulates the quantity of sunshine that may cross via to a mild sensor attached to audio system by the use of an amplifier.

[Emily] used a couple of razor blades fastened to a 3-D revealed bracket to create the masks, and a TI OPT101 mild sensor in conjunction with a mild supply to decode the optical sign. She attempted to make use of a photoresistor and a discrete photodiode, however neither had the desired sensitivity. She constructed a body with adjustable positions for an loafer pulley and the optical reader unit, an electronics field on one finish for the digital parts, and some other pulley hooked up to a stepper motor to cycle a brief loop of the movie.

Most of the initiatives we see involving movie this present day are for growing virtual copies. You can digitize your previous 35 mm picture movie the use of a (*2*)(*12*) Pi, some Lego items, and a DSLR digicam, or do the similar for 8 mm movie with a 3-D revealed rig.