diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -1,4 +1,15 @@
 # Geiger-interface
+### Hardware
+**RadiationD v1.1 (CAJOE)** it's a cheap(est) Geiger counter that you can found on China market. I recommend to order assembled ;) due lacks of documentations. Next one is ESP32. I like generic dev boards like **ESP32-WROOM-32** - they are cheap, have many gpio, now they have even USB-C ;) Let's go connect it together. My CAJOE arrived with DuPont jumper wire, but don't be confused: **VIN** on CAJOE is an signal output! After everything is connected, you can flash ESP with **Geiger-interface.ino**. On first boot, WiFiManager create access point named **ESP_xxxxxx**. After connect there will be captive portal (or under address http://192.168.4.1) where you can configure:
+- Wifi connection
+- MQTT server address
+- GMC accound and geiger ID
+
+After **save** interface should connect to Wifi and send data :) If you provide wrong data you can enable captive portal by double reset of ESP.
+
+About hardware: Interface should works with any geiger counter that output a pulse signal.
+
+**DISCLAIMER:** I'm know that I am bad programmer, so feel free to send me fixes or improvements
 
 ### GMC.MAP integration
 - Create account on https://www.gmcmap.com/
@@ -43,6 +54,8 @@ reload configuration and voilà!
 
 > *Dead Time for J305 based on the data from the Internet, since the datasheets from suppliers do not contain this data.
 
+About J305 Tube conversion factor, you can read intresting article on: https://iot-devices.com.ua/en/geiger-tube-j305-how-to-calculate-the-conversion-factor-of-cpm-technical-note-en/
+
 ### Resources
 - https://iot-devices.com.ua/
 - https://www.gmcmap.com/