This project is a fully discrete 24-hour digital desk clock designed and built using classic 4000 series CMOS logic ICs only. The goal of this project was to create a reliable and easy-to-understand digital clock without using any microcontrollers, firmware, or programmable logic.

The clock is based on a 32.768kHz crystal time base, divided down to a precise 1 Hz signal using CMOS divider and flip-flop ICs. Time counting is done with BCD counters, and each digit is displayed using seven-segment LED displays driven by BCD-to-seven-segment decoder ICs. All logic, counting, decoding, and control functions are implemented purely in hardware.

The entire circuit operates from a regulated 5V supply and consumes approximately 200mA. To keep the project true to its retro and handmade nature, the circuit is constructed on perfboard using point-to-point wiring and mounted inside a homemade picture frame built from molded PVC frame bars.

This project was primarily built as a learning exercise, a celebration of classic digital logic design, and a decorative "fully handmade" addition to my home workshop.

• Fully discrete CMOS logic design
• 24-hour time format
• Display seconds, minutes, and hours
• Crystal-controlled timekeeping
• Hardware-based time setting controls
• Seven-segment LED display
• Powered from 5V DC

The complete bill of materials for this project is available here.

This project is released as an open hardware design under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. You are free to use, modify, and share the design with proper attribution.