Reverse-engineering a $35 backup camera display (AMT630A)
A reverse-engineered video processor in a cheap composite backup display can draw a programmable HUD: this Arduino library drives the AMT630A’s on-screen-display engine from an ESP32 over I²C, with multiple windows, custom glyphs, 16-color bitmaps, palettes, and animation.
The README documents real-board testing and important firmware-specific limits. In particular, sustained external-I²C control can contend with the monitor’s stock MCU and freeze the display pipeline on the tested unit; the workaround described applies only to that firmware, so other boards need independent validation.
The Hacker News thread appreciated the reverse-engineering work and video, while asking for clearer hardware photos. The author noted that the chip supports up to three composite sources, but input switching is not yet implemented in the library.