ET-S44

MPR121 12-Channel Touch Sensor

Name: MPR121 12-Channel Touch Sensor
Brand: ElectroTrical
SKU: ET-S44
Price: 22.00 AED
Availability: OutOfStock

12 capacitive touch inputs over I²C

AED 22.00

Out of stock

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Download datasheet (PDF)

Overview Key features Specifications Performance Pinout

Overview

12 capacitive touch inputs over I²C

The ET-S44 is built around the NXP MPR121 — 12 electrodes + proximity (13th virtual), auto-calibration, per-channel thresholds, 8 LED-capable GPIO. It connects over I²C 0x5A–0x5D (IRQ) and is powered from VIN 3.3–5.5V, onboard LDO (IC 1.71–3.6V).

Two Qwiic / STEMMA QT connectors let you chain it with other boards without soldering, and the 2.54 mm header fits a breadboard.

Designed in Dubai by ElectroTrical — the full schematic, BOM and design notes are published below.

Good for

Touch keyboards and pianos
Interactive art
Fruit and conductive-paint controls

Key features

What makes it different

IC

NXP MPR121: 12 electrodes + proximity (13th virtual), auto-calibration, per-channel thresholds, 8 LED-capable GPIO

Interface

I2C 0x5A–0x5D, IRQ

Supply

VIN 3.3–5.5V, onboard LDO (IC 1.71–3.6V)

Libraries

Adafruit_MPR121 / CircuitPython, SparkFun MPR121, ESPHome mpr121

Qwiic / STEMMA QT

Two JST-SH connectors plus a 2.54 mm header — 3.3 V and 5 V hosts.

Open documentation

Schematic, BOM and layout notes published for every board.

Specifications

Technical specifications

Device
IC	NXP MPR121: 12 electrodes + proximity (13th virtual), auto-calibration, per-channel thresholds, 8 LED-capable GPIO
Interface	I2C 0x5A–0x5D, IRQ
Supply	VIN 3.3–5.5V, onboard LDO (IC 1.71–3.6V)

Board
Size	50.8 × 25.4 mm
Mounting	4 × M2.5 holes, 2.54 mm from each corner
Connectors	2 × Qwiic / STEMMA QT (JST SH 4-pin) · 6-pin 2.54 mm header
Main IC	MPR121QR2 (LCSC C91322)
Revision	Rev B

Software
Libraries	Adafruit_MPR121 / CircuitPython, SparkFun MPR121, ESPHome `mpr121`

Solder jumpers
JP1 (default Closed)	Cut to turn off the LED
JP2 (default Closed)	Cut to remove the host-side I2C pull-ups
JP3 (default 2–3 (GND))	ADDR: GND = 0x5A, 3V3 = 0x5B (SDA/SCL options 0x5C/0x5D by wire)

Performance

Response settings

Electrode sampling intervalNXP MPR121 datasheet. Short intervals respond faster; long intervals save power.

1 ms1 ms

2 ms2 ms

4 ms4 ms

8 ms8 ms

16 ms16 ms

32 ms32 ms

64 ms64 ms

128 ms128 ms

Pinout

Pin map and connections

Pin	Name	Type	Function
1	`VIN`	Power	3.3–5.5V
2	`3V3`	Power	LDO output
3	`GND`	Ground	Ground
4	`SCL`	I²C	I²C clock
5	`SDA`	I²C	I²C data
6	`IRQ`	Output	Touch change, active low, host level

Qwiic / STEMMA QT pins: GND, VIN, SDA, SCL (same on both connectors). I²C pull-ups (10 kΩ) are on the board; cut JP2 to remove them.

Mechanical

Dimensions and what's in the box

Board 50.8 × 25.4 mm with M2.5 holes — Top view · 50.8 × 25.4 mm

In the box

1 × ET-S44 MPR121 12-Channel Touch Sensor (assembled)
1 × 6-pin 2.54 mm male header, unsoldered

Getting started

Plug in a Qwiic / STEMMA QT cable, or solder the header and wire VIN, GND, SDA and SCL
Libraries: Adafruit_MPR121 / CircuitPython, SparkFun MPR121, ESPHome mpr121
Run an I²C scanner to confirm the address: 0x5A, 0x5D

Compare

Which input board?

	MPR121 12-Channel Touch Sensor (this board)This board	ET-S25 APDS-9960 Gesture & Colour Sensor
What it does	12 capacitive touch inputs over I²C	Gesture, proximity, RGB colour and light
Interface	I²C 0x5A–0x5D, IRQ	I²C fixed 0x39, INT
Best for	Touch keyboards and pianos	Touchless gesture control
Price	22 AED	23 AED

Downloads

Documents and design files

PDFET-S44 schematicRev B LCSCMPR121QR2 datasheet and stockC91322

STEP3D modelComing soon

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