A companion app for the DIY Geiger counter module GGreg20_V3, developed by the IoT-devices team for a quick and convenient start.

Important Note
This app, like the GGreg20_V3 module, is not a precise measuring device. It's intended for personal use, hobbies, learning, and creative experiments, not as a finished product. It's for DIY electronics enthusiasts.

Benefits of Using GGreg20_V3 with This App
- Cost-Effective: No need for controllers like Arduino, ESP8266, ESP32, or Raspberry Pi.

- Easy to Use: No programming skills required.

- Wireless: No soldering or connecting cables.

- Quick Setup: No device searching or pairing.

- Broadcasting: One Geiger counter can be used simultaneously by multiple users.

How It Works
GGreg20_V3 users only need the powered module (per documentation) and this smartphone app. Wireless data transfer from the GGreg20_V3 module to your smartphone uses sound signals from its built-in buzzer. The app filters sounds from your smartphone's microphone, recognizing only those that match the GGreg20_V3 buzzer signals.

Data Provided
The app displays:

- CPM (counts per minute)

- Measurement cycle seconds count (1-minute duration)

- Current radiation level uSv/hour (calculated minute-by-minute)

Radiation Level Formula: uSv/hour = CPM * CF

Settings
On the settings screen, you can adjust:

- Thresholds for received pulses (in Hz)

- Conversion Factor (CF) for the Geiger tube on GGreg20_V3
You can also save or restore default settings.

Known Limitations
The wireless audio channel can cause false readings or inaccuracies in noisy environments.

Specifically:

- While GGreg20_V3 can measure all pulses from tubes like J305, SBM20, or LND712 in high-radiation conditions, this app is limited. An artificial 70-millisecond delay between perceived pulses was implemented to differentiate them. This restricts the app to correctly processing radiation levels only up to 850 CPM (or 3 uSv/hour). This is adequate for everyday use but insufficient for nuclear disaster scenarios.

- The app effectively filters specific frequencies, but signal clutter (e.g., from nearby conversations) can cause overlaps, leading the app to ignore relevant pulses.

- Echo issues with relevant signals occur in enclosed spaces. You might see this effect in videos where the buzzer pulses once, but the app counts it twice, likely due to echo. (For video recording, we use a lightbox where the echo occurs.)

Important Reminder
This is an educational, demonstration, and testing app for beginners. Choose appropriate tools for specific tasks.

Technical Details
Developed with MIT App Inventor 2, the app uses the com.KIO4_Frequency Extension. This is a non-commercial, free-of-charge product.