“A frequency counter with a waveform display function. You can also specify which part of the input waveform you want to count.
This can be made using a PIC with a built-in high speed ADC. However, since the pin spacing of the selected PIC is 0.5mm pitch, it was necessary to make a printed circuit board.
Thinking of printing a simple chassis with a 3D printer, too. (But I also like bare PCBs..)”