RadiationMetrix: Compact IoT-based Geiger Counter for Environmental Radiation Monitoring

Ionizing radiation monitoring is essential for environmental safety, nuclear incident response, public health protection, and academic research. This paper presents RadiationMetrix, a portable and low cost IoT enabled Geiger counter designed using the Raspberry Pi Pico W microcontroller and the DFRobot Gravity Geiger Counter Module (SEN0463). The system integrates an SSD1306 OLED display for local data visualization and uses the Blynk IoT platform to enable real time cloud based monitoring, logging, and alerting of counts per minute (CPM) and dose rate (?Sv/h). The firmware uses interrupt driven pulse counting to ensure accurate detection, while Wi Fi connectivity enables remote access, threshold based alerts, and automated analytics. Experimental evaluation demonstrates stable background readings between 0.10–0.20 ?Sv/h, reliable connectivity, and portable battery powered performance. With its open source architecture, compact 3D printed enclosure, and affordability, RadiationMetrix provides an accessible platform for citizen science, educational laboratories, and distributed environmental radiation surveillance.