# Adafruit MPR121 12-Key Capacitive Touch

> Adafruit 1982 MPR121 12-channel capacitive touch breakout (STEMMA QT): NXP MPR121 senses 12 electrodes (pads, foil, wire) and reports touch/release over I2C (0x5A–0x5D via ADDR) with an interrupt pin, 3–5 V supply with regulator, 33.0 × 19.3 mm board — touch-sensitive skin zones for a robot shell or hand.

- Manufacturer: Adafruit Industries
- Part number: 1982
- Category: Tactile & touch sensors
- Canonical page: https://www.xirkit.io/products/adafruit-mpr121-12-key-capacitive-touch-b241
- Pinout: https://www.xirkit.io/products/adafruit-mpr121-12-key-capacitive-touch-b241/pinout
- Structured JSON: https://www.xirkit.io/products/adafruit-mpr121-12-key-capacitive-touch-b241/data.json
- Source: Xirkit structured parts catalog — every value traced to a cited document; unknowns are explicit.

## Key specifications

| Property | Value |
| --- | --- |
| Sensing | capacitive |
| Active area shape | electrodes |
| Touch channels | 12 |
| Output | touch / release status per electrode over I2C + interrupt |
| Interface | i2c |
| Supply voltage | 3–5 V |
| Dimensions | 33.02 × 19.3 × 1.6 mm |

## Pinout (7 pins, 0 with electrical limits)

| Pin | Position | Kind | Chip pad | Functions | VIH | VIL | VOH | VOL | IOH | IOL | 5 V tolerant |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Vin | — | power in | — | power_in | — | — | — | — | — | — | — |
| 3Vo | — | power in | — | power_in | — | — | — | — | — | — | — |
| GND | — | ground | — | ground | — | — | — | — | — | — | — |
| SCL | — | i2c scl | — | scl | — | — | — | — | — | — | — |
| SDA | — | i2c sda | — | sda | — | — | — | — | — | — | — |
| ADDR | — | address | — | addr | — | — | — | — | — | — | — |
| INT | — | interrupt | — | int | — | — | — | — | — | — | — |

## Where to buy

| Supplier | Price | Stock | Checked | URL |
| --- | --- | --- | --- | --- |
| www.adafruit.com | 7.95 USD | in_stock | 2026-09-29 | https://www.adafruit.com/product/1982 |

## FAQ

**What voltage powers the Adafruit MPR121 12-Key Capacitive Touch?**

Supply range 3–5 V.

**How much does the Adafruit MPR121 12-Key Capacitive Touch cost?**

From $7.95 at www.adafruit.com. Prices are observed unit prices before tax and shipping.

**What are the Adafruit MPR121 12-Key Capacitive Touch dimensions?**

33.02 × 19.3 × 1.6 mm. A STEP model is available for enclosure fit checks.

**Where does this Adafruit MPR121 12-Key Capacitive Touch data come from?**

Every value in this record is traced to a source — 2 documents including the board and chip datasheets — with the page and table cited per value. Unknowns are left explicit, never guessed.

## Sources

- [Adafruit MPR121 12-Key Capacitive Touch datasheet](https://cdn-learn.adafruit.com/downloads/pdf/adafruit-mpr121-12-key-capacitive-touch-sensor-breakout-tutorial.pdf)
- [www.adafruit.com listing](https://www.adafruit.com/product/1982)

## Part graph

### Built from

- MPR121 — sensor on the Adafruit MPR121 12-Key Capacitive Touch

### Alternatives (by use case)

- [Adafruit AT42QT1010 Capacitive Touch (momentary)](https://www.xirkit.io/products/adafruit-at42qt1010-capacitive-touch-momentary-ba53) — Both serve touch and force sensing — check the trade-offs; $5.95 vs $7.95
- [Alpha MF02A Square FSR 38 mm (1–49 N)](https://www.xirkit.io/products/alpha-mf02a-square-fsr-38-mm-1-49-n-09b0) — Both serve touch and force sensing — check the trade-offs; $5.95 vs $7.95