ESP32-S31 integrates Espressif’s next-generation capacitive touch sensor (Touch Sensor), providing up to 14 touch input channels and 3 proximity sensor channels. The module supports a wide range of touch interactions—buttons, sliders, touch panels, and more—for smart home, wearables, smart toys, electronic instruments, industrial control, and similar applications.

High Immunity Design

The ESP32-S31 Touch Sensor has been redesigned at the hardware level for high electromagnetic interference (EMI) environments, with significantly improved immunity. It supports three-frequency synchronized sampling, with hardware sampling rates up to 20 MHz, reducing interference that can occur at a single sampling frequency. Built-in advanced touch algorithms and intelligent filtering deliver stable, accurate touch detection even under rigorous EMC test conditions such as conducted susceptibility (CS) injection, helping end products pass certification more reliably.

Matrix Keypad Demo

With 14 independent touch input channels, developers can configure them as standalone keys or combine them into a high-density matrix keyboard. The driver recognizes single-tap, double-tap, long-press, and other complex touch events, and allows per-channel sensitivity tuning. The module also supports touch wake-up from deep sleep: the chip monitors touch activity at very low standby power and wakes the system quickly when triggered, extending battery life on battery-powered devices.

Multi-Dimensional Touch Interaction Demo

ESP32-S31 supports touch sampling up to 20 MHz for faster, more precise capacitance sensing. Beyond smooth slider and wheel operation, algorithms can extend to pressure sensing, velocity detection, and basic gesture recognition. Three dedicated proximity sensor channels enable accurate contactless interaction—such as wake-on-approach and hand-wave detection—for more advanced product designs.

1. Pressure sensing

2. Direction detection

3. Gesture recognition

Rapid Tuning Tools

To move beyond the traditional “black box” of capacitive touch tuning, Espressif provides a dedicated Touch Sensor visualization and tuning tool. Following the wizard, developers can quickly complete the entire workflow, from hardware calibration to parameter optimization. The tool supports real-time dynamic waveform monitoring and data-stream analysis, showing the relationship between charge/discharge baselines and trigger thresholds so engineers can understand the underlying behavior and accelerate production-ready deployments.

1. Self-calibration

2. Multi-frequency testing

3. Guided mode

Resources

For the next-generation Touch Sensor, Espressif will soon release a complete software development toolkit and a rich set of application examples. Stay tuned. Follow the Espressif website for the latest development resources and technical support, and use ESP32-S31 to build the next generation of standout interactive products.