oc74 video synthesizer
The oc74 is an experimental platform to explore the relationship between electrical signals and the visual phenomena they create on screen. A video synthesizer is like an electronic music synthesizer but instead of producing signals we will hear as sound, it produces varying Red Green and Blue color channel signals which are interpreted by a monitor as a continuous stream of images. Depending on the varying signals we send, the signals that the monitor is expecting, along with the resolution and refresh rate of the monitor in question, the raw color signals synthesized will result in different visual compositions.
More specifically, the oc74 is an 8-bit VGA video synthesizer made mostly of the 74x logic family including binary counters, adders, encoders, boolean gates and multiplexers, along with more traditional amplifiers and filters. The device allows one to “patch” together inputs and outputs from different modules, creating different signal pathways. VGA signals can also be input and mixed with generated signals to produce a large range of visual phenomena.
The circuit, designed in Eagle, is engraved on a one-sided PCB with a fiber laser cutter.
The oc74 is organized in a diagrid formation, with inputs aligned with one side of the diamond and outputs along the opposide side. Using female-female jumpers, the output from one module can be connected to the input of the another. Not only can modules be chained together but signal pathways can interact on one another, modifying the way they interact to inputs in complex, time-varying ways.
The housing for the oc74 is CNC flip-milled block of HDPE, leaving headers and knobs accessible to the knob-twister.