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 # IoT Geiger Counter with ESP32, OLED Display and Thingspeak Channel
 
-- Measures radioactive gamma and beta radiation with already quite good resolution at the typical low levels of the background radiation (due to the big STS-6 tube)
+- Measures radioactive gamma and beta radiation with quite good resolution at the typical low levels of the natural radiation (due to the big STS-6 tube)
 - Displays the current counts per minute (CPM), estimated dose equivalent rate in micro-Sievert per hour (µS/h) and 10 minutes history with 5 second resolution as bargraph
 ![Circuit Board](media/geiger-counter-pcb.jpg)
 - Low-power mode for use with batteries, OLED display and click sounds on, WiFi off
@@ -11,19 +11,19 @@ Feel free to use this project as a base for your own projects AT YOUR OWN RISK!
 
 # Hardware
 
-- Russian Geiger counter tube STS-6 at 400 V with ~5 MΩ series resistor
+- Russian Geiger counter tube STS-6 (CTC-6) at 400 V with ~5 MΩ series resistor
 - High voltage circuit from ArnoR at mikrocontroller.net https://www.mikrocontroller.net/topic/380666, schematic https://www.mikrocontroller.net/attachment/273334/HystereseStepUpTLC555-2.png. *Keep the high-voltage capacitor small to avoid dangerous charges! For safety avoid any contact with the high voltage parts!*
 - ~400 µs pulse generation using Geiger tube series resistors as voltage divider, high impedance input to darlington transistor and TLC 555 timer for rectangle pulse generation
 - ESP32 board Wemos Lolin32
 - OLED 128x64 with controller SH1106 at I2C
-- Voltage supply from either USB or power supply or 3x 1.5V AAA batteries, circuit works from 3.0 V up to 5.0 V
+- Voltage supply from either USB or power supply or 3x 1.5V AAA batteries, circuit works stable from 3.0 V up to 5.0 V
 - Pulse input is expected at GPIO 18 (high pulses with at least about 250 µs length)
 - Switch for WiFi mode is expected at GPIO 4 (low=WiFi mode, high=low-power mode)
 - OLED I2C bus is expected at GPIO 22 (SCK) and 21 (SDA)
 
 # Software
 
-- PlatformIO project using Arduino library, ESP-IDF for sleep functions and U8g2 for display output
+- [PlatformIO VSCode project](https://github.com/platformio/platformio-vscode-ide) using [Arduino](https://github.com/arduino/Arduino) library, [Espressif ESP-IDF](https://github.com/espressif/esp-idf) for sleep functions and [U8g2](https://github.com/olikraus/u8g2) for display output
 - Low-power mode uses light sleep, a wake-up for each signal pulse change and a wake-up every 1000 ms to update pulse statistics and OLED. This results in about 90% sleep. Could be improved using deep sleep and ULP. However, light sleep is already quite good and much easier.
 - WiFi mode uses no sleep and simple interrupts for pulse counting. Pulse statistics and OLED are updated every 1000 ms, data is sent to thingspeak every 60 s.
 - Credentials (WiFi SSID, password, thingspeak channel key) are only declared in `credentials.h` and must be defined in a `credentials.cpp`