Modern infrastructure fails silently. Networks disguise outages behind cached UIs, cloud services evaporate without warning, and digital news can distort reality—all while the physical world unravels unnoticed. This unsettling truth inspired Heartbeat-Sentinel, an experimental project that asks: "Is the world still running—or am I just offline?" Developed on GitHub, it combines a Raspberry Pi with a software-defined radio (SDR) to create a standalone 'doomsday detector' that monitors real-world signals, bypassing the internet as a single point of failure.

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How It Works: Sensing Civilization’s Pulse

At its core, Heartbeat-Sentinel uses cheap, accessible hardware to track multiple independent indicators, ensuring redundancy and reducing false positives. The system cross-references data from seven key categories:

Category Indicator
Internet Global routing, DNS roots, multi-continent pings
Power Local AC power via sentinel device
Wireless Nearby Wi-Fi SSIDs vs. household power
Broadcast FM radio carriers, DVB-T multiplexes
Cellular GSM beacons (via SDR) and modem attach checks
Air Traffic ADS-B aircraft signals
Navigation GNSS satellite lock and count
Amateur Radio APRS packet presence

This multi-sensor approach avoids 'internet tunnel vision.' For instance, if Wi-Fi vanishes but FM radio broadcasts persist, the system flags it as a local network issue—not societal collapse. Anomalies are analyzed using logic rules or an optional local LLM (like Llama or Mistral) to explain deviations, such as a sudden drop in air traffic during peak hours. All processing occurs on-device, ensuring operation during total internet blackouts.

Why This Isn’t Just Another Sensor Project

Heartbeat-Sentinel stands out by prioritizing physics over packets. As the project starkly notes: "> Networks hide outages behind cached UIs. Cloud services collapse silently. News can lie, physics can’t." This ethos drives its design:
- Anti-false-positive mechanisms: Cross-validation between signals (e.g., cellular beacons vs. power grid status) prevents overreactions to isolated glitches.
- Edge-resilient architecture: With zero cloud dependencies, it runs entirely on a Raspberry Pi, making it viable for remote or disaster-stricken areas.
- Citizen-led transparency: It democratizes monitoring, allowing anyone to verify systemic stability without trusting centralized authorities.

For developers, this highlights critical lessons in resilient system design: favoring diverse data sources, minimizing external dependencies, and leveraging edge AI for real-time analysis. It’s a blueprint for 'technological existentialism'—engineering systems that question their own reliability.

Status and Joining the Build

Currently a work-in-progress, the project invites contributors to refine signal processing, add sensors (e.g., seismic or radiation monitors), or enhance its LLM integration. As an open-source MIT-licensed initiative , it emphasizes ethical use: "> This project exists to promote civil resilience, transparency and peace. Do not use it for fearmongering, coercion, surveillance, or harm."

Building Heartbeat-Sentinel isn’t about paranoia—it’s about preparedness. In a world of escalating cyber threats and climate disruptions, this Raspberry Pi device redefines resilience, reminding us that sometimes, the most honest truths come not from a server, but from the silent hum of a radio wave.

Source: Heartbeat-Sentinel on GitHub