A wonderful counter project is described by the author on his page.

http://leoniv.diod.club/projects/audio/e-004/e-004_counter/e-004_counter.html

I'm planning the following changes to his design:

• Replacing the microcontroller with STM32
• Removing all unnecessary connectors from the board. Since the new system will use a serial interface for communication between the nodes
• Using a more standard JTAG connector