2 layers101.6 × 53.3 mm

Mouseboard
nmz787/rs232-sniffer
I needed a microcontroller-controlled RS-232 serial mouse, and had an Arduino Mega 2560 laying around.
17 partsGPL-2.0
Boards in 1 GitHub repository, designed in KiCad, that use the SP3238ECA by SIPEX (0℃~+70℃ 250Kbps RS-232 - Interface - Specialized). See how each wires it, with its parts, size, README and files; the SP3238ECA’s symbol, footprint and pinout are on its own page.

nmz787/rs232-sniffer
I needed a microcontroller-controlled RS-232 serial mouse, and had an Arduino Mega 2560 laying around.