2 layers85 × 85 mm

Boards in 3 GitHub repositories, designed in KiCad, that use the ITR20001/T by Everlight Electronics (20mA 5mm DIP-4 Reflective Optical Interrupters ROHS). See how each wires it, with its parts, size, README and files; the ITR20001/T’s symbol, footprint and pinout are on its own page.

nbourre/ATtiny1616WithLineTracker
ATtiny1616 Line Tracker compatible with MakeBlock robots

yzxoi/stm32-ir-linescan-digit-recognizer
An STM32G0B1-based 8-channel infrared line-scan digit recognizer with custom KiCad hardware, USB-UART acquisition, Q15 preprocessing, and TinyML inference.