The frequency counter is the most popular instrument in the home maid instruments.
I think that the reason why it is built widely is: it can be built easily because it is digital circuit, it is generic measurement and many construction kits are available.
Many electronics hobbyists will experienced to build any frequency counter.
This project is second trial for me.
But building two ordinaly frequency counter is not smart so that some additional functions ware impremented to the frequency counter.
The function is not that abundant compared to generic universal counter however it can measure pulse period/width besides frequency, I named this project "Universal Counter".