The device can operate completely locally. Measurement records are stored as CSV files on a microSD card and the latest readings can be viewed directly from a browser on the local network. An optional remote logging function can also send the measurements to a web server.
Main Features
- WIZnet W55RP20-EVB-PICO controller with wired Ethernet
- J305 Geiger-Müller tube
- CPS and CPM measurement
- Approximate radiation level in µSv/h and µR/h
- HDC1080 temperature and humidity sensor
- PCF8563 real-time clock
- NTP time synchronization over Ethernet
- microSD CSV data logging
- Local AJAX web dashboard
- Historical graph and SD-card log browser
- Optional HTTP/HTTPS remote server logging
- Remote server configuration stored in flash memory
Hardware
The W55RP20-EVB-PICO handles Ethernet communication, pulse counting, sensor acquisition, RTC communication and SD-card access.
A dedicated high-voltage section generates the operating voltage required by the Geiger-Müller tube. Each detected pulse is converted into a logic-level signal and counted by the microcontroller.
Local Web Dashboard
After receiving an IP address from the router using DHCP, the device can be accessed directly from a web browser. No application or cloud service is required.
The dashboard displays the current radiation level, CPM, CPS, temperature, humidity, dew point and calculated heat index. Live values are updated in the background using AJAX.
microSD Data Logging
Measurements are periodically written to CSV files on the microSD card. Each record contains the RTC timestamp, environmental measurements, pulse counts, CPS, CPM and calculated radiation values.
The web interface can read the SD-card history and display the latest records as a graph. Older records can also be browsed directly from the local dashboard.
Remote Server Logging
Remote logging is optional. When enabled, each successfully stored local measurement can also be sent to a remote HTTP or HTTPS endpoint.
The remote server URL, Sensor ID, API Key and API Secret can be configured from the device's web interface and are stored in flash memory.
Safety Notice
The Geiger-Müller tube section generates several hundred volts. Appropriate high-voltage safety precautions must be taken when assembling, testing or modifying the circuit.
The µSv/h value is calculated using an approximate conversion factor for the J305 tube. This project is intended for experimentation, education and environmental monitoring. It is not a calibrated dosimeter or a certified radiation safety instrument.
