Like many of us, [Emily] ii found herself locked in a COVID-19 over the summer. To make the most of her time on her own, she assembled an optical audio decoder for old 16 mm film, built using state-of-the-art components and a bit of 3D printing.
It all started with a broken 16 mm projector that was [Emily] received from a friend. After repairing and testing the projector with a roll of film purchased at a flea market, she discovered that the film contained an audio record that her projector could not play. The audio path is coded as a moving strip of different widths, and when a mask with a narrow slit is placed over it it changes the amount of light that can pass through to a load-connected light sensor. -peak through amplifier.
[Emily] they used a pair of razor blades mounted to 3D printed braces to create the mask, and a TI OPT101 light sensor along with a light source to decode the optical signal. She tried to use a separate photoresistor and photodiode, but neither had the necessary sensitivity. She built a frame with adjustable positions for the idler puller and the optical reader unit, an electronic box on one end for the electronic parts, and another puller connected to a stepper motor to ride a short loop of the film.
Most of the projects we see include film these days to create digital copies. You can digitize your old 35 mm photo film using a Raspberry Pi, some Lego pieces, and a DSLR camera, or do the same for an 8 mm film with 3D printed string. Keep reading “Listening to long-forgotten voices: an optical audio decoder for 16 Mm film”
Most of the data storage devices we currently use are, at heart, two-dimensional. Yes, multiple platters may be in solid format, but the data storage takes place on a flat surface. Even an optical driver is effectively one surface that holds data. At New York City College, they are trying to store data in three dimensions using lab-grown diamonds and LASERs.
Diamonds with few defects are usually more valuable. But in this application, the researchers take advantage of the flaws to store information. Optical memory that uses volume instead of surface is not entirely new. However, it is difficult to use these techniques in a rewritable way.
Diamonds are the crystalline structure of carbon atoms. Sometimes, however, a carbon atom is missing from the structure. That is a blank space. Another defect is when a nitrogen atom replaces a carbon atom. Sometimes there is a blank space next to a false nitrogen atom and that causes an NV center (nitrogen blank space).
Keep reading “Diamonds for data storage”