A Distance Meter that uses no MCU. Bases on ultrasonic ranging module HC-SR04.
The schematic employs just three standard logic ICs (8-bit counter, divider/oscillator, quad NAND) and a ROM chip (acts as a binary-to-decimal converter).
no-mcu-distance-meter-kicad5-prj/- KiCAD 5.1 project with the schematic and PCB designeprom-programmer- Arduino sketch to program the ROM chip using mega2560 (see the sketch for the connections info).
CC BY-NC 4.0 © github.com/AlexIII