ESPGeiger

ESPGeiger is an open-source project that turns an ESP8266 or ESP32 into an IoT-connected Geiger counter. It collects, calculates and reports radiation levels from a range of Geiger counters with pulse or serial outputs.

• 😃 Easy to install via web browser — no compiler required
• ✅ Works with generic pulse counters and GC10, GC10next, MightyOhm serial counters
• 📈 Built-in web server with live graphing
• 🔴 Live CPM and μSv/h readings
• 🔢 Smoothed values over 1, 5 and 15 minutes
• 🖥️ Optional SSD1306 OLED display and WS2812X NeoPixel status light
• 📟 Accurate counting via interrupt or ESP32 hardware counter (PCNT)
• 🌐 MQTT, Home Assistant auto-discovery, Radmon.org, GMCMAP, ThingSpeak, custom Webhooks
• 💾 Optional SD card logging
• 🚧 Test builds for emulating pulse and serial counters

Quick Start

The easiest way to install ESPGeiger is the Web Installer — it runs in your Chrome or Edge browser and flashes your device over USB. No code editor or compiler required.

👉 https://install.espgeiger.com

Select your build from the dropdown and follow the on-screen instructions. Installation takes about two minutes.

Which Build Do I Need?

Pick the build that matches your hardware. If in doubt, start with Pulse — it works with most generic Geiger counters.

I have an ESP + generic pulse Geiger counter

Hardware	Recommended Build
ESP8266 (Wemos D1 Mini, NodeMCU, etc.)	esp8266_pulse
ESP8266 with SSD1306 OLED	esp8266oled_pulse
ESP32	esp32_pulse
ESP32 with SSD1306 OLED	esp32oled_pulse
CAJOE IoT-GM (ESP32 with built-in OLED)	esp32_cajoe_iotgm

I have an ESP + serial Geiger counter

Counter	ESP8266 Build	ESP32 Build
GC10	esp8266_gc10	esp32_gc10
GC10-Next	esp8266_gc10next	esp32_gc10next
MightyOhm	esp8266_mightyohm	esp32_mightyohm

OLED variants exist for each — replace esp8266_ with esp8266oled_ (or esp32_ with esp32oled_).

I have an ESPGeiger-HW or ESPGeiger Log

These are official ESPGeiger hardware kits — use the hardware-specific builds:

Hardware	Pulse	GC10	GC10-Next	MightyOhm
ESPGeiger-HW	espgeigerhw	—	—	—
ESPGeiger Log	espgeigerlog	espgeigerlog_gc10	espgeigerlog_gc10next	espgeigerlog_mightyohm

I want to test without a real Geiger counter

Test builds emulate a Geiger counter internally. You can also wire the TXPIN of one ESPGeiger to the RXPIN of another to simulate a serial counter:

Build	Description
esp8266_test / esp32_test	Internal counter, no output
esp8266_testpulse / esp32_testpulse	Outputs Poisson-distributed pulses on TXPIN
esp8266_test_gc10 / esp32_test_gc10	Emulates a GC10 serial counter
esp8266_test_mightyohm / esp32_test_mightyohm	Emulates a MightyOhm serial counter

See the full list of available builds on the releases page or in the build targets documentation.

Hardware Connection

By default GEIGER_RXPIN is set to GPIO13. Connect your Geiger counter's pulse or serial TX output to this pin. Don't forget a common ground.

First-time Setup

1. After flashing, connect to the new Wi-Fi network (ESPGeiger-XXXXXX)
2. A captive portal should pop up — if not, browse to http://192.168.4.1/
3. Select your home Wi-Fi network and enter the password
4. Once connected, browse to http://ESPGeiger-XXXXXX.local or the assigned IP
5. Configure MQTT, Radmon, GMCMAP, ThingSpeak and other outputs from the Config page

Upgrading

Upgrades can be done over-the-air through the web interface. Please be careful to select the right firmware for your hardware.

Note: ESP32 users should use the firmware binary when upgrading (the merged binaries are for fresh installs via the Web Installer).

Documentation

Full documentation is available at docs.espgeiger.com.

Building from Source

If you want to customise the firmware or create a build for unsupported hardware, you can build from source using PlatformIO. See the Platformio Build documentation for details.

Compatible Geiger Counters

Pulse

• DIY GeigerKit
• NetIO GC10
• RHElectronics
• GeigerHV
• GGreg20
• MightyOhm Kit (can also be used as a pulse counter)
• DiY-GDC
• CAJOE (and clones) RadiationD-v1.1

Serial

• GC10 / GC10-Next
• MightyOhm
• ESPGeiger-HW

Other serial-based counters should be supportable with small additions to the codebase. If you have one not listed, please raise an issue.

Announcing ESPGeiger-HW

The official IoT Geiger counter powered by ESPGeiger. See docs.espgeiger.com for more information.

Contributions

Contributions are welcome — please feel free to raise a Pull Request or open an issue.

Thanks 🙏

Supporting libraries:

• WiFiManager
• AsyncHTTPRequest_Generic
• ESPNtpClient
• Smoothed
• ArduinoJson

Inspiration:

• OpenMQTTGateway
• tinyGS
• FreqCountESP