In this talk, we’ll begin by contextualizing the importance of the seismic alert in Mexico City, a system born from the devastating 1985 earthquake. We’ll examine how it was designed, how it works, and why it carries such a deep psychological impact.

From there, we’ll explore the history and design of Weather Radio and the SAME protocol, looking at how messages are transmitted and encoded through this technology, and how it was later adapted for SASMEX.

I’ll also share my personal experience building compatible receivers, from early open-source experiments that inspired local manufacturers to create government-certified devices, to developing a receiver as part of my undergraduate thesis.

We’ll analyze how simplicity, one of the key strengths of these systems, also introduces certain risks, and how these trade-offs emerge when dealing with accessibility, interoperability, and security in system design.

Finally, I’ll demonstrate how to receive, decode, and encode these alert messages, and discuss how, with the right equipment, it’s possible to generate such alert signals.