TTP223 Capacitive Touch Sensor
Touch-sensitive pad for replacing mechanical buttons — perfect for clean, sealed enclosures.
A capacitive touch-sensing breakout that swaps a physical button for a solid-state touch pad, common in enclosure-friendly builds. Built around the TTP223 capacitive touch IC, it detects the small capacitance change caused by a finger touching (or even approaching through a thin non-metal panel) its copper pad, outputting a simple digital HIGH/LOW signal — a clean way to add a button-like input to a project without any moving parts or a hole cut in the enclosure.
Specifications
| Sensor type | TTP223 capacitive touch sensor IC |
| Operating voltage | 2.0V–5.5V DC |
| Operating current | ~1.5-3 µA in standby, low active current |
| Output modes | Toggle mode or momentary (direct) mode, selectable via a solder jumper on most breakout boards |
| Output logic | Active HIGH by default on most modules (some variants can be configured active LOW) |
| Touch-through thickness | Can sense through a few millimeters of non-conductive material (plastic, glass, acrylic), useful for sealed enclosures |
| Response time | ~60ms typical |
| Interface | Single digital output pin, read directly as a HIGH/LOW input |
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power, 2.0–5.5V DC |
| 2 | GND | Ground |
| 3 | SIG (OUT) | Digital output — goes HIGH when touched (in direct/momentary mode), or toggles state on each touch (in toggle mode) |
A small solder jumper pad on the back of most TTP223 breakout boards selects between momentary mode (output HIGH only while actively touched) and toggle mode (output flips between HIGH and LOW with each separate touch) — check which mode your board is configured for before wiring up your project logic, since it changes how you should read the pin in code.
Variants
Pick momentary mode when you want press-and-hold behavior (like a typical button), or toggle mode for an on/off style switch. If the project needs more than one or two touch points, the MPR121 handles up to 12 channels over I2C far more cleanly than wiring multiple individual TTP223 breakouts.
| Variant | Temp range | Hum range | Accuracy | Protocol | Price |
|---|---|---|---|---|---|
| TTP223 breakout (momentary mode) | ~$0.50-1.50 | ||||
| TTP223 breakout (toggle mode) | ~$0.50-1.50 | ||||
| MPR121 (multi-channel capacitive touch) | ~$3-6 |