analog video posterisation effect – adapted from a Rob Schafer design

SKU: P005 Category:


the two_comparator_effect circuit is a compact analog video effect device (similar to a guitar effect pedal but for video!) available as a pcb, kit or assembled and tested unit. check out the video below to see example of the effect.

it takes any composite video signal as input and converts this into a “posterized” version – contrasting black, white and grey segments – whose levels are configurable with the two threshold dials


the design is adapted from an example created by Rob Schafer for his whiteboard_schoolhouse youtube series. this is a perfect beginner project for anyone getting started with video-art making instruments. (but also powerful as part of a larger and more complex signal chain)

this project – like everything in the underscores catalog – is fully open-source hardware – find all the source plus lots more information and guides on the github repo:

Additional information

Weight 130 g
video format


input type


output type


power supply

5v, barrel jack – center positive