MicroPython MPR121

MicroPython driver for MPR121 capacitive touch keypads and breakout boards.

Compatible with:

• SparkFun Capacitive Touch Keypad - MPR121 (discontinued)
• MPR121 Capacitive Touch Keypad
• MPR121 Capacitive Touch Breakout Board

These boards use 3.3V logic, so you would want to use a logic level converter with this for 5V systems.

Examples

Copy the file to your device, using ampy, webrepl or compiling and deploying. eg.

$ ampy put mpr121.py

Basic usage

from machine import Pin, I2C
import mpr121
import time

i2c = I2C(scl=Pin(5), sda=Pin(4))
mpr = mpr121.MPR121(i2c, 0x5A)

while True:
	print(mpr.touched())
	time.sleep_ms(100)

For more detailed examples, see /examples

Parts

• MPR121 Capacitive Touch Keypad $2.88 AUD
• Female-Female Dupont wires $0.64 AUD
• VCC-GND STM32F407VET6 mini $15.47 AUD
• TinyPICO $20.00 USD
• Wemos D1 Mini $5.20 AUD

Connections

VCC GND STM32F407VET6 Mini

from machine import I2C
import mpr121
i2c = I2C(3)
mpr = mpr121.MPR121(i2c, 0x5A)

MPR121	STM32F407VET6
VCC	3V3 (or 5V)
IRQ	D3 (optional)
SCL	A8 (SCL)
SDA	C9 (SDA)
GND	GND

• I2C(1) SCL=B6, SDA=B7
• I2C(2) SCL=B10, SDA=B11
• I2C(3) SCL=A8, SDA=C9

TinyPICO (ESP32)

from machine import Pin, I2C
import mpr121
i2c = I2C(scl=Pin(22), sda=Pin(21))
mpr = mpr121.MPR121(i2c, 0x5A)

MPR121	TinyPICO ESP32
VCC	3V3
IRQ	GPIO32 (optional)
SCL	GPIO22 (SCL)
SDA	GPIO21 (SDA)
GND	GND

Wemos D1 Mini (ESP8266)

from machine import Pin, I2C
import mpr121
i2c = I2C(scl=Pin(5), sda=Pin(4))
mpr = mpr121.MPR121(i2c, 0x5A)

MPR121	D1 Mini ESP8266
VCC	3V3
IRQ	D3 (optional)
SCL	D1 GPIO5 (SCL)
SDA	D3 GPIO4 (SDA)
GND	GND

Links

• micropython.org
• MPR121 datasheet
• MPR121 product page
• Adafruit Ampy

License

Licensed under the MIT License.

Copyright (c) 2018 Mike Causer