A geiger counter prop that detects bluetooth devices and produces clicking sounds and indicator light
The Geiger Counter project began as a direct spin-off from the StAlkErS Personal Dosimeter system. The core Bluetooth proximity technology already existed and had proven itself in live games. What was missing was a mechanic that encouraged players to move toward something deliberately, rather than avoid it.
The dosimeter was designed around risk and consequence. The Geiger counter was designed around search and discovery.
Internally, the Geiger counter reuses the same ESP32 and Bluetooth scanning approach as the personal dosimeters. The hardware driving the broadcast beacons is identical, with “gamma sticks” simply being a renamed version of the existing RAD sticks. The separation is handled entirely in software, with distinct Bluetooth names ensuring the two systems ignore each other completely.
This allowed both mechanics to operate side by side in the same event without interference or confusion.
The original dosimeter firmware tracked accumulated radiation over time. For the Geiger counter, this logic was removed entirely. The sketch was simplified to focus on proximity detection only, translating signal strength into audio clicks and LED escalation.
Early testing revealed the same limitation seen in the dosimeters, with three to four second scan cycles causing players to overshoot targets. The code was reworked to increase scan frequency and decouple LED updates from Bluetooth scans, creating a far more responsive and readable experience in motion.
Rather than retrofitting real-world Geiger counters, a hollow classic-style yellow shell was used. The enclosure is clearly 3D printed, lightweight, and not intended as a museum replica. Five large LEDs and an oversized switch were chosen for clarity under stress, prioritising usability over realism.
In play, the Geiger counter became a trusted seek tool. Players used it to locate buried alien artefacts, identify specific objects within clusters, or scan NPCs to identify irradiated individuals. Unlike the dosimeter, there is no personal penalty associated with proximity, which shifts player behaviour from caution to curiosity.
The project validated the flexibility of the underlying dosimeter technology. A future version could return to real-world donor shells with analogue needles, but the core system is already proven. More importantly, it demonstrated that the same technical foundation can support multiple, opposing gameplay mechanics through thoughtful interaction design alone.
An in game radiation dosimeter detection system for the StAlkErS Filmsim events.
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