UPDATE: This is the new version v2 of our popular FDC1004 breakout board. This version adds QWIIC connection capability with two QWIIC connectors on either sides. This allows to you to quickly (or maybe qwiic’ly) connect to Sparkfun’s QWIIC range of boards without any soldering required. This board still has the same headers as the previous one in addition to the QWIIC connectors and is fully backwards-compatible.
The FDC1004 is a single-chip IC for capacitance measurement for application including proximity sensing and liquid level sensing. This is based on the concept of measuring capacitance of an electrode with respect to ground.
This breakout board contains everything to connect it to an Arduino’s I2C pins and it can be connected to any other platform with support for I2C two-wire interfaces.
We have made several cool projects with it including proximity sensing and liquid-level sensing from the outside of a tank. Check out our Hackster page (hackster.io/protocentral) for the detailed project description.
Capacitive Liquid-level sensing using this board
Check it out on 
Features
- Breakout contains the Texas Instruments FDC1004 IC
- 4 channel measurement
- On-board 3.3V voltage regulator
- Output data rates up to 400 Samples/second
- Easy-to-use I2C interface
Specifications
- Capacitance measurement range: +/- 15 pF
- Resolution: 0.5 fF
- Maximum offset capacitance: 100 pF
Barry Jensen –
Works fine on original Arduino MEGA and Nano 33 BLE. Does not work with my ESP32 board (Firebeetle ESP32) and there is really no support out there that I can find for the problems using this board with the ESP32 when programming on the Arduino IDE.