Lukas Fässler from Soldernerd published a project writeup showing how he built a PIC-based beacon keyer:
This is likely the first ham radio related project that I document here on this blog
But my very first PIC project was a beacon keyer that I made for my father, HB9BBD. That was in 2013. A beacon keyer is a great project to get started with microcontrollers since it’s not much more than a fancy way of blinking an LED.