TTP224 4-Channel Capacitive Touch Switch – Digital Touch Sensor Module

Description

The TTP224 4-Channel Capacitive Touch Switch Module is a four-key digital touch sensor board designed to replace traditional mechanical buttons with a modern, contactless interface. It is built around the TonTouch TTP224 touch pad detector IC, which independently handles four touch pads with four direct output pins, converting each touch into a clean digital signal .

The module operates from a wide supply voltage of 2.4V to 5.5V, making it directly compatible with Arduino, ESP32, ESP8266, Raspberry Pi, and most microcontroller platforms . It features ultra-low power consumption, drawing typically 2.5µA in low-power mode and 13µA in fast mode at 3V . The response time is approximately 60ms in fast mode and 160ms in low-power mode .

A key feature of the TTP224 is its high configurability via onboard pad options. Users can select between direct (momentary) mode and toggle (latching) mode, CMOS or open-drain output, active-high or active-low polarity, and single-key or multi-key operation . Each channel also has a maximum on-time setting (120s/64s/16s/infinite) to prevent accidental continuous activation . The module includes four state indicator LEDs, one per channel, for visual feedback during development .

Critical limitations: The TTP224 is a digital switch, not an analog sensor—it provides HIGH/LOW output per channel, not proportional touch-strength readings. The sensing area is on the PCB; while it can detect touch through non-metallic materials like glass or plastic, metal objects near the sensor can cause false triggers . The module has a 0.5-second stabilization period after power-on during which touches are ignored . The output can only source/sink a few milliamps (typically 8mA sink, 4mA source at 3V)—use a transistor or relay for higher-current loads .

Features

• 4 Independent Touch Channels: Each pad has its own direct output pin (OUT1–OUT4) for simultaneous multi-key detection .

• Wide Operating Voltage (2.4V–5.5V): Compatible with 3.3V and 5V systems .

• Ultra-Low Power Consumption: 2.5µA (low-power mode) to 13µA (fast mode) at 3V .

• Configurable Output Modes: Direct or toggle, CMOS or open-drain, active-high or active-low via pad options .

• Single-Key or Multi-Key Operation: Selectable via the SM pin .

• Maximum On-Time Protection: Configurable 16s/64s/120s/infinite to prevent stuck-key outputs .

• Touch-Through-Panel Capable: Detects touch through glass, plastic, and acrylic (up to ~5mm) .

• 4-Channel State Indicator LEDs: Onboard LEDs show which channel is active .

Technical Specifications