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esp-idf-mpr121/README.md
2025-06-14 13:24:07 +09:00

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esp-idf-mpr121

MPR121 Capacitive Touch Driver for esp-idf.

I ported from here.

Software requirements

ESP-IDF V4.4/V5.x.
ESP-IDF V5.0 is required when using ESP32-C2.
ESP-IDF V5.1 is required when using ESP32-C6.

Hardware requirements

MPR121 Capacitive Touch switch.

mpr121-1

Installation

git clone https://github.com/nopnop2002/esp-idf-mpr121
cd esp-idf-mpr121
idf.py set-target {esp32/esp32s2/esp32s3/esp32c2/esp32c3/esp32c6}
idf.py menuconfig
idf.py flash

Configuration

Image Image

I2C Port selection

XTENSA's ESP32 has two i2c port: I2C_NUM_0/1.
You can use these two ports freely.
If you use this module at the same time as another I2C device using I2C port 0, you must change it to I2C port 1.

Wirering

MPR121 ESP32 ESP32-S2/S3 ESP32-C2/C3/C6
SCL -- GPIO19 GPIO12 GPIO6
SDA -- GPIO18 GPIO11 GPIO5
IRQ -- GPIO15 GPIO18 GPIO4
GND -- GND GND GND
VCC -- 3.3V 3.3V 3.3V

Note: It is recommended to add external pull-up resistors for SDA/SCL pins to make the communication more stable, though the driver will enable internal pull-up resistors.

You can change it to any pin using menuconfig.

Screen Shot

mpr121-2

Supports multiple simultaneous touches.

I (55786) MAIN: electrode 0 was just touched
I (55786) MAIN: electrode 1 was just touched
I (55786) MAIN: electrode 2 was just touched
I (55786) MAIN: electrode 3 was just touched
I (58446) MAIN: electrode 0 was just released
I (58446) MAIN: electrode 1 was just released
I (58446) MAIN: electrode 2 was just released
I (58446) MAIN: electrode 3 was just released

How to use this component in your project

Create idf_component.yml in the same directory as main.c.

YourProject --+-- CMakeLists.txt
              +-- main --+-- main.c
                         +-- CMakeLists.txt
                         +-- idf_component.yml

Contents of idf_component.yml.

dependencies:
  nopnop2002/mpr121:
    path: components/mpr121
    git: https://github.com/nopnop2002/esp-idf-mpr121.git

When you build a projects esp-idf will automaticly fetch repository to managed_components dir and link with your code.

YourProject --+-- CMakeLists.txt
              +-- main --+-- main.c
              |          +-- CMakeLists.txt
              |          +-- idf_component.yml
              +-- managed_components ----- nopnop2002__mpr121

Reference

https://github.com/nopnop2002/esp-idf-ttp229