Simple test

Ensure your device works with this simple test.

examples/mpr121_simpletest.py
 1# SPDX-FileCopyrightText: 2017 Tony DiCola for Adafruit Industries
 2# SPDX-License-Identifier: MIT
 3
 4# Simple test of the MPR121 capacitive touch sensor library.
 5# Will print out a message when any of the 12 capacitive touch inputs of the
 6# board are touched.  Open the serial REPL after running to see the output.
 7# Author: Tony DiCola
 8import time
 9
10import board
11import busio
12
13# Import MPR121 module.
14import adafruit_mpr121
15
16# Create I2C bus.
17i2c = busio.I2C(board.SCL, board.SDA)
18
19# Create MPR121 object.
20mpr121 = adafruit_mpr121.MPR121(i2c)
21
22# Note you can optionally change the address of the device:
23# mpr121 = adafruit_mpr121.MPR121(i2c, address=0x91)
24
25# Loop forever testing each input and printing when they're touched.
26while True:
27    # Loop through all 12 inputs (0-11).
28    for i in range(12):
29        # Call is_touched and pass it then number of the input.  If it's touched
30        # it will return True, otherwise it will return False.
31        if mpr121[i].value:
32            print(f"Input {i} touched!")
33    time.sleep(0.25)  # Small delay to keep from spamming output messages.
examples/mpr121_piano.py
 1# SPDX-FileCopyrightText: 2017 Tony DiCola, Carter Nelson for Adafruit Industries
 2# SPDX-License-Identifier: MIT
 3
 4# MPR121 piano demo.
 5# Listens to the first 7 inputs of the MPR121 and plays a middle scale note
 6# when an input is touched.  Note only one note is played at a time!
 7# For use with microcontrollers or computers with PWM support only!
 8
 9
10import board
11import busio
12import pwmio
13
14# Import MPR121 module.
15import adafruit_mpr121
16
17# Configure PWM buzzer and other state:
18BUZZER_PIN = board.D9
19TONE_ON_DUTY = 2**15  # Duty cycle of tone when turned on, a square wave.
20TONE_OFF_DUTY = 0  # Duty cycle of tone when turned off, 0 or no signal.
21NOTE_FREQS = [
22    261,  # Input 0 = 261 hz = middle C
23    294,  # Input 1 = middle D
24    329,  # Input 2 = middle E
25    349,  # Input 3 = middle F
26    392,  # Input 4 = middle G
27    440,  # Input 5 = middle A
28    493,  # Input 6 = middle B
29    0,  # Input 7 = nothing (set to a frequency in hertz!)
30    0,  # Input 8
31    0,  # Input 9
32    0,  # Input 10
33    0,
34]  # Input 11
35
36
37# Create I2C bus.
38i2c = busio.I2C(board.SCL, board.SDA)
39
40# Create MPR121 class.
41mpr121 = adafruit_mpr121.MPR121(i2c)
42# Note you can optionally change the address of the device:
43# mpr121 = adafruit_mpr121.MPR121(i2c, address=0x91)
44
45# Setup buzzer PWM output.
46buzzer = pwmio.PWMOut(BUZZER_PIN, duty_cycle=TONE_OFF_DUTY, frequency=440, variable_frequency=True)
47
48last_note = None
49while True:
50    # Get touched state for all pins
51    touched = mpr121.touched_pins
52    # If no pins are touched, be quiet
53    if True not in touched:
54        last_note = None
55        buzzer.duty_cycle = TONE_OFF_DUTY
56        continue
57    # Get index of touched pin
58    note = touched.index(True)
59    # Play note if pin is different and has a defined note
60    if note != last_note and NOTE_FREQS[note] != 0:
61        last_note = note
62        buzzer.frequency = NOTE_FREQS[note]
63        buzzer.duty_cycle = TONE_ON_DUTY