This is a complete EC sensor, suitable for use with Arduino, NodeMCU, WeMOS and similar microcontrollers.

For a detailed write-up on this sensor and how it works, please visit https://create.arduino.cc/projecthub/wvmarle/ec-tds-sensor-337b19

Driver libraries for Arduino are available on Github: https://github.com/wvmarle/Arduino_ECSensor (currently supported processors: various ATtiny, ATmega328 and 2560, ESP8266).