Protocentral FDC2214 4-Channel Capacitance-to-Digital Converter Breakout (Qwiic)

Deciding between the FDC1004 and FDC2214? The FDC2214 is the higher-resolution, EMI-resistant choice (28-bit, LC-tank resonant sensing) for proximity, gesture, conductive-liquid level and material measurement. If you need absolute capacitance, or level sensing of non-conductive liquids where hands come near the tank, the FDC1004 breakout and its active shield drivers may suit better — see our FDC1004 vs FDC2214 comparison.

The Protocentral FDC2214 Breakout brings Texas Instruments’ resonant-sensing capacitance-to-digital converter to an easy-to-use, Qwiic-enabled board. The FDC2214 is a 4-channel, 28-bit capacitive-sensing front-end that measures the resonant frequency of an external LC tank — an EMI-resistant, narrow-band technique with a 0.3 fF noise floor (at 100 SPS) that holds up in electrically noisy environments.

Because it senses changes in capacitance, the sensor can be any metal or conductor — a strip of copper tape is enough. Wave a hand near an electrode, watch liquid rise inside a tank, detect a button press through a panel, or measure displacement, moisture and material composition — all over a simple two-wire I²C interface.

Getting started: Install the Protocentral FDC2214 Arduino library — search for ProtoCentral_FDC2214_Capacitance in the Arduino IDE Library Manager, or download it from GitHub — then run the 03_MultiChannelAutoScan example to stream all four channels over I²C.

Open hardware: The complete KiCad design — schematic, PCB layout and the exported schematic PDF — lives in the FDC2214 hardware repository, released under the CERN-OHL-P v2 licence.

Features

• Texas Instruments FDC2214 — 4-channel, 28-bit capacitance-to-digital converter
• EMI-resistant LC-based measurement for stable readings in noisy environments
• Four onboard LC tanks (18 µH + 33 pF, ≈6.5 MHz) — connect your own sensor electrodes to IN0–IN3
• Wide sensor-frequency range: 10 kHz to 10 MHz
• Two Qwiic / STEMMA QT connectors for solder-free daisy-chaining, plus 0.1″ breadboard headers
• Selectable I²C address (0x2B default / 0x2A) via onboard ADDR solder jumper
• Onboard 3.3 V regulator — runs from 3.3 V or 5 V; I²C is level-shifted for 3.3–5 V hosts
• INTB interrupt and SD (shutdown) pins broken out — these connect directly to the 3.3 V FDC2214, so don’t drive or pull them up to 5 V
• Open-source hardware (CERN-OHL-P v2)

Applications

• Proximity and gesture sensing
• Non-contact liquid-level sensing through a tank wall, including conductive liquids such as soap and ink
• Material analysis and moisture sensing
• Capacitive buttons, sliders and touch panels
• Linear and rotational position / displacement sensing
• Bubble and slug detection in tubing (slow flows)

Specifications

• Sensor: Texas Instruments FDC2214
• Channels: 4 (multiplexed)
• Resolution: 28-bit at maximum conversion time; 0.3 fF noise floor at 100 SPS
• Maximum sample rate: 4.08 kSPS (single channel, at reduced resolution)
• Sensor excitation frequency: 10 kHz – 10 MHz
• Interface: I²C (up to 400 kHz), address 0x2B (default) / 0x2A
• Supply: 3.3 V – 5 V (onboard regulator)
• Connectors: 2× Qwiic + 0.1″ headers