This is an Audio Tone Burst Generator using a Raspberry Pi Pico and an AD9833 sine wave generator for measuring the delay through a piece of audio equipment.

A GPS module is used the receive GPS signals and display the exact time on a 16x2 LCD. If the number of GPS satellites received drops below a certain number it means one of the following: (1) A huge coronal mass ejection from the Sun has wiped out the GPS system and probably the Power Grid, too; (2) A Global Thermonuclear War has started; or (3) An extraterrestrial ship is hovering over your home and the ETs are getting ready to abduct you. See http://www.jmargolin.com/pico-projects-e1/