Once you've finished setting up your Feather RP2040 with CircuitPython, you can access the code and necessary libraries by downloading the Project Bundle.
To do this, click on the Download Project Bundle button in the window below. It will download as a zipped folder.
# SPDX-FileCopyrightText: 2023 Liz Clark for Adafruit Industries
# SPDX-License-Identifier: MIT
from random import randint
import ulab.numpy as np
import board
import audiobusio
import audiomixer
import synthio
import simpleio
from adafruit_ticks import ticks_ms, ticks_add, ticks_diff
from adafruit_ht16k33 import segments
from adafruit_ht16k33.matrix import Matrix8x8x2
from adafruit_seesaw import seesaw, rotaryio, digitalio
SAMPLE_RATE = 44100
SAMPLE_SIZE = 256
VOLUME = 5000
# waveforms, envelopes and synth setup
square = np.concatenate((np.ones(SAMPLE_SIZE//2, dtype=np.int16)*VOLUME,np.ones(SAMPLE_SIZE//2,
dtype=np.int16)*-VOLUME))
sine = np.array(np.sin(np.linspace(0, 4*np.pi, SAMPLE_SIZE, endpoint=False)) * VOLUME,
dtype=np.int16)
saw = np.linspace(VOLUME, -VOLUME, num=SAMPLE_SIZE, dtype=np.int16)
noise = np.array([randint(-VOLUME, VOLUME) for i in range(SAMPLE_SIZE)], dtype=np.int16)
lfo = synthio.LFO(rate = .5, waveform = sine)
amp_env0 = synthio.Envelope(attack_time=0.1, decay_time = 0.1, release_time=0.1,
attack_level=1, sustain_level=0.05)
amp_env1 = synthio.Envelope(attack_time=0.05, decay_time = 0.1, release_time=0.1,
attack_level=1, sustain_level=0.05)
# synth plays the notes
synth = synthio.Synthesizer(sample_rate=SAMPLE_RATE)
# these are the notes
synth0 = synthio.Note(frequency = 0.0, envelope=amp_env0, waveform=square, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth1 = synthio.Note(frequency = 0.0, envelope=amp_env1, waveform=sine, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth2 = synthio.Note(frequency = 0.0, envelope=amp_env0, waveform=square, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth3 = synthio.Note(frequency = 0.0, envelope=amp_env1, waveform=sine, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synths = [synth0, synth1, synth2, synth3]
wave_names = ["SQUR", "SINE", "SAW ", "NOIZ"]
waveforms = [square, sine, saw, noise]
synth0_wave = 0
synth1_wave = 1
synth2_wave = 0
synth3_wave = 1
# i2s amp setup
audio = audiobusio.I2SOut(bit_clock=board.D10, word_select=board.D11, data=board.D9)
mixer = audiomixer.Mixer(voice_count=4, sample_rate=SAMPLE_RATE, channel_count=1,
bits_per_sample=16, samples_signed=True, buffer_size=2048 )
audio.play(mixer)
vol_val = 2
mixer.voice[0].play(synth)
mixer.voice[0].level = 0.3
# these are the triads, all major
c_tones = [130.81, 164.81, 196.00]
g_tones = [196.00, 246.94, 293.66]
d_tones = [146.83, 185.00, 220.00]
a_tones = [220.00, 277.18, 329.63]
e_tones = [164.81, 207.65, 246.94]
b_tones = [246.94, 311.13, 369.99]
fsharp_tones = [185.00, 233.08, 277.18]
csharp_tones = [138.59, 174.61, 207.65]
aflat_tones = [207.65, 261.63, 311.13]
eflat_tones = [155.56, 196.00, 233.08]
bflat_tones = [233.08, 293.66, 349.23]
f_tones = [174.61, 220.00, 261.63]
# names for the alphanumeric displays
chord_names = ["Cmaj", "Gmaj", "Dmaj", "Amaj", "Emaj", "Bmaj",
"F#ma", "C#ma", "Abma", "Ebma", "Bbma", "Fmaj"]
chords = [c_tones, g_tones, d_tones, a_tones, e_tones, b_tones, fsharp_tones, csharp_tones,
aflat_tones, eflat_tones, bflat_tones, f_tones]
# i2c setup
i2c = board.I2C()
# the encoders
seesaw0 = seesaw.Seesaw(i2c, addr=0x49)
seesaw1 = seesaw.Seesaw(i2c, addr=0x4A)
seesaw2 = seesaw.Seesaw(i2c, addr=0x4B)
seesaw3 = seesaw.Seesaw(i2c, addr=0x4C)
menu_seesaw = seesaw.Seesaw(i2c, addr=0x4D)
# the alphanumeric displays
display0 = segments.Seg14x4(i2c, address=0x70)
display1 = segments.Seg14x4(i2c, address=0x71)
display2 = segments.Seg14x4(i2c, address=0x72)
display3 = segments.Seg14x4(i2c, address=0x73)
menu_display = segments.Seg14x4(i2c, address=0x74)
# the matrix
matrix0 = Matrix8x8x2(i2c, address=0x75)
seesaws = [seesaw0, seesaw1, seesaw2, seesaw3, menu_seesaw]
buttons0 = []
buttons1 = []
buttons2 = []
buttons3 = []
menu_buttons = []
button0_states = []
button1_states = []
button2_states = []
button3_states = []
menu_states = []
button0_names = ["Select", "Up", "Left", "Down", "Right"]
# setup the buttons on all of the encoders
for i in range(1, 6):
seesaw0.pin_mode(i, seesaw0.INPUT_PULLUP)
seesaw1.pin_mode(i, seesaw1.INPUT_PULLUP)
seesaw2.pin_mode(i, seesaw2.INPUT_PULLUP)
seesaw3.pin_mode(i, seesaw3.INPUT_PULLUP)
menu_seesaw.pin_mode(i, menu_seesaw.INPUT_PULLUP)
buttons0.append(digitalio.DigitalIO(seesaw0, i))
buttons1.append(digitalio.DigitalIO(seesaw1, i))
buttons2.append(digitalio.DigitalIO(seesaw2, i))
buttons3.append(digitalio.DigitalIO(seesaw3, i))
menu_buttons.append(digitalio.DigitalIO(menu_seesaw, i))
button0_states.append(False)
button1_states.append(False)
button2_states.append(False)
button3_states.append(False)
menu_states.append(False)
# make all of the encoders
encoder0 = rotaryio.IncrementalEncoder(seesaw0)
last_position0 = 0
encoder1 = rotaryio.IncrementalEncoder(seesaw1)
last_position1 = 0
encoder2 = rotaryio.IncrementalEncoder(seesaw2)
last_position2 = 0
encoder3 = rotaryio.IncrementalEncoder(seesaw3)
last_position3 = 0
menu_enc = rotaryio.IncrementalEncoder(menu_seesaw)
last_menuPosition = 0
# Python Implementation of Björklund's Algorithm by Brian House
# MIT License 2011
# https://github.com/brianhouse/bjorklund
def bjorklund(steps, pulses):
steps = int(steps)
pulses = int(pulses)
if pulses > steps:
raise ValueError
pattern = []
counts = []
remainders = []
divisor = steps - pulses
remainders.append(pulses)
level = 0
while True:
counts.append(divisor // remainders[level])
remainders.append(divisor % remainders[level])
divisor = remainders[level]
level = level + 1
if remainders[level] <= 1:
break
counts.append(divisor)
def build(level):
if level == -1:
pattern.append(0)
elif level == -2:
pattern.append(1)
else:
for _ in range(0, counts[level]):
build(level - 1)
if remainders[level] != 0:
build(level - 2)
build(level)
p = pattern.index(1)
pattern = pattern[p:] + pattern[0:p]
return pattern
# using ticks for time tracking
clock = ticks_ms()
# default BPM
bpm = 120
# beat divison
beat_div = [15, 30, 60, 120, 240]
beat_index = 2
beat_names = ["1/16", "1/8 ", "1/4 ", "1/2 ", "HOLE"]
delay = int((beat_div[beat_index] / bpm) * 1000)
# variables for euclidean
c0 = 0
c1 = 0
c2 = 0
c3 = 0
r0 = 0
r1 = 0
r2 = 0
r3 = 0
last_r0 = 0
last_r1 = 0
last_r2 = 0
last_r3 = 0
euclid0_steps = 8
euclid0_pulses = 4
euclid1_steps = 8
euclid1_pulses = 4
euclid2_steps = 8
euclid2_pulses = 4
euclid3_steps = 8
euclid3_pulses = 4
rhythm0 = bjorklund(euclid0_steps, euclid0_pulses)
rhythm1 = bjorklund(euclid1_steps, euclid1_pulses)
rhythm2 = bjorklund(euclid2_steps, euclid2_pulses)
rhythm3 = bjorklund(euclid3_steps, euclid3_pulses)
# read buttons to update Euclidean rhythms
# pylint: disable=too-many-branches
def read_buttons(button_array, button_states, euc, e_step, e_pulse, the_step):
for b in range(5):
if not button_array[b].value and button_states[b] is False:
button_states[b] = True
if button0_names[b] == "Select":
e_step = 8
e_pulse = 4
if the_step >= e_step:
the_step = 0
elif button0_names[b] == "Up":
if e_step > 16:
e_step = 16
else:
e_step += 1
elif button0_names[b] == "Down":
if e_step < 1:
e_step = 1
else:
e_step -= 1
if the_step >= e_step:
the_step = 0
elif button0_names[b] == "Left":
e_pulse -= 1
e_pulse = max(e_pulse, 1)
else:
e_pulse += 1
e_pulse = min(e_pulse, e_step)
euc = bjorklund(e_step, e_pulse)
if button_array[b].value and button_states[b] is True:
button_states[b] = False
if button0_names[b] in ("Select", "Up", "Down"):
matrix0.fill(matrix0.LED_OFF)
draw_steps(euclid0_steps, 0)
draw_steps(euclid1_steps, 2)
draw_steps(euclid2_steps, 4)
draw_steps(euclid3_steps, 6)
return euc, e_step, e_pulse, the_step
# play euclidean rhythms and update matrix
def play_euclidean(this_synth, n, the_rhythm, rhythm_count, last_count, c, matrix_slot):
if last_count <= 7:
matrix0[matrix_slot, last_count] = matrix0.LED_GREEN
else:
c -= 1
matrix0[matrix_slot + 1, (last_count - last_count) + c] = matrix0.LED_GREEN
c += 1
if the_rhythm[rhythm_count] == 1:
this_synth.frequency = n[randint(0, 2)]
synth.press(this_synth)
if rhythm_count <= 7:
matrix0[matrix_slot, rhythm_count] = matrix0.LED_RED
else:
matrix0[matrix_slot + 1, (rhythm_count - rhythm_count) + c] = matrix0.LED_RED
c += 1
else:
synth.release(this_synth)
if rhythm_count > 7:
c += 1
last_count = rhythm_count
rhythm_count += 1
if rhythm_count >= len(the_rhythm):
rhythm_count = 0
if rhythm_count == 1:
c = 0
return rhythm_count, last_count, c
# initial matrix draw
def draw_steps(euc_steps, col):
dif = 0
for m in range(euc_steps):
if m <= 7:
matrix0[col, m] = matrix0.LED_GREEN
else:
matrix0[col + 1, (m - m) + dif] = matrix0.LED_GREEN
dif += 1
draw_steps(euclid0_steps, 0)
draw_steps(euclid1_steps, 2)
draw_steps(euclid2_steps, 4)
draw_steps(euclid3_steps, 6)
# clocks for playing euclidean and reading menu encoder
enc_clock = ticks_ms()
menu_clock = ticks_ms()
# the modes menu
modes = ["PLAY", "EUC ", "BPM ", "BEAT", "ADSR", "WAVE", "RING", "LFO ", "VOL "]
mode_index = 0
mode = modes[mode_index]
menu_display.print(f" {mode}")
# default chords
chord0_sel = 0
chord1_sel = 1
chord2_sel = 0
chord3_sel = 1
display0.print(chord_names[chord0_sel])
display1.print(chord_names[chord1_sel])
display2.print(chord_names[chord2_sel])
display3.print(chord_names[chord3_sel])
# arrays of individual buttons
select_buttons = [buttons0[0], buttons1[0], buttons2[0], buttons3[0]]
left_buttons = [buttons0[2], buttons1[2], buttons2[2], buttons3[2]]
right_buttons = [buttons0[4], buttons1[4], buttons2[4], buttons3[4]]
select_states = [button0_states[0], button1_states[0], button2_states[0], button3_states[0]]
left_states = [button0_states[2], button1_states[2], button2_states[2], button3_states[2]]
right_states = [button0_states[4], button1_states[4], button2_states[4], button3_states[4]]
select_index = 0
left_index = 0
right_index = 0
# adsr mode
adsr_names = ["A", "D", "S", "R"]
synth_adsr_indexes = [0, 0, 0, 0]
adsr_properties = [0, 1, 4, 2]
adsr0_values = [amp_env0.attack_time, amp_env0.decay_time,
amp_env0.sustain_level, amp_env0.release_time]
adsr1_values = [amp_env1.attack_time, amp_env1.decay_time,
amp_env1.sustain_level, amp_env1.release_time]
adsr2_values = [amp_env0.attack_time, amp_env0.decay_time,
amp_env0.sustain_level, amp_env0.release_time]
adsr3_values = [amp_env1.attack_time, amp_env1.decay_time,
amp_env1.sustain_level, amp_env1.release_time]
all_adsr_values = [adsr0_values, adsr1_values, adsr2_values, adsr3_values]
adsr0_val = int(simpleio.map_range(amp_env0.attack_time, 0.0, 1.0, 0, 19))
adsr1_val = int(simpleio.map_range(amp_env0.decay_time, 0.0, 1.0, 0, 19))
adsr2_val = int(simpleio.map_range(amp_env0.sustain_level, 0.0, 1.0, 0, 19))
adsr3_val = int(simpleio.map_range(amp_env0.release_time, 0.0, 1.0, 0, 19))
clock_stretch = False
ring0_val = 0
ring1_val = 0
ring2_val = 0
ring3_val = 0
lfo_val = 0
# used to play/pause
play_states = [True, True, True, True]
while True:
# rotary encoder reading
if ticks_diff(ticks_ms(), enc_clock) >= 100:
position0 = encoder0.position
position1 = encoder1.position
position2 = encoder2.position
position3 = encoder3.position
menuPosition = menu_enc.position
# menu changes mode
if menuPosition != last_menuPosition:
if menuPosition > last_menuPosition:
mode_index = (mode_index + 1) % len(modes)
else:
mode_index = (mode_index - 1) % len(modes)
if mode in ("EUC ", "ADSR"):
clock_stretch = True
if mode in ("PLAY", "BPM ", "BEAT", "WAVE") and clock_stretch:
clock = ticks_ms()
clock_stretch = False
mode = modes[mode_index]
menu_display.print(f" {mode}")
last_menuPosition = menuPosition
# encoder functionality depends on mode
# encoder 0 has most functionality
if position0 != last_position0:
if position0 > last_position0:
if mode == "PLAY":
chord0_sel = (chord0_sel + 1) % len(chords)
display0.print(chord_names[chord0_sel])
elif mode == "BEAT":
beat_index = (beat_index + 1) % 5
delay = int((beat_div[beat_index] / bpm) * 1000)
display0.print(f" {beat_names[beat_index]}")
elif mode == "BPM ":
bpm += 1
delay = int((beat_div[beat_index] / bpm) * 1000)
display0.print(f" {bpm}")
elif mode == "ADSR":
adsr0_val = (adsr0_val + 1) % 20
mapped_val = simpleio.map_range(adsr0_val, 0, 19, 0.0, 1.0)
all_adsr_values[0][synth_adsr_indexes[0]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[0][0],
decay_time = all_adsr_values[0][1],
release_time=all_adsr_values[0][3],
attack_level=1, sustain_level=all_adsr_values[0][2])
synth0.envelope = the_env
elif mode == "WAVE":
synth0_wave = (synth0_wave + 1) % len(wave_names)
synth0.waveform = waveforms[synth0_wave]
elif mode == "RING":
ring0_val = (ring0_val + 1) % 25
mapped_val = simpleio.map_range(ring0_val, 0, 24, 0.0, 220.0)
synth0.ring_frequency = mapped_val
elif mode == "LFO ":
lfo_val = (lfo_val + 1) % 10
mapped_val = simpleio.map_range(lfo_val, 0, 9, 0.0, 5.0)
lfo.rate = mapped_val
elif mode == "VOL ":
vol_val = (vol_val + 1) % 10
mapped_val = simpleio.map_range(vol_val, 0, 9, 0.0, 1.0)
mixer.voice[0].level = mapped_val
else:
if mode == "PLAY":
chord0_sel = (chord0_sel - 1) % len(chords)
display0.print(chord_names[chord0_sel])
elif mode == "BEAT":
beat_index = (beat_index - 1) % 5
delay = int((beat_div[beat_index] / bpm) * 1000)
display0.print(f" {beat_names[beat_index]}")
elif mode == "BPM ":
bpm -= 1
display0.print(f" {bpm}")
elif mode == "ADSR":
adsr0_val = (adsr0_val - 1) % 20
mapped_val = simpleio.map_range(adsr0_val, 0, 19, 0.0, 1.0)
all_adsr_values[0][synth_adsr_indexes[0]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[0][0],
decay_time = all_adsr_values[0][1],
release_time=all_adsr_values[0][3],
attack_level=1, sustain_level=all_adsr_values[0][2])
synth0.envelope = the_env
elif mode == "WAVE":
synth0_wave = (synth0_wave - 1) % len(wave_names)
synth0.waveform = waveforms[synth0_wave]
elif mode == "RING":
ring0_val = (ring0_val - 1) % 25
mapped_val = simpleio.map_range(ring0_val, 0, 24, 0.0, 220.0)
synth0.ring_frequency = mapped_val
elif mode == "LFO ":
lfo_val = (lfo_val - 1) % 10
mapped_val = simpleio.map_range(lfo_val, 0, 9, 0.0, 5.0)
lfo.rate = mapped_val
elif mode == "VOL ":
vol_val = (vol_val - 1) % 10
mapped_val = simpleio.map_range(vol_val, 0, 9, 0.0, 1.0)
mixer.voice[0].level = mapped_val
last_position0 = position0
if position1 != last_position1:
if position1 > last_position1:
if mode == "PLAY":
chord1_sel = (chord1_sel + 1) % len(chords)
display1.print(chord_names[chord1_sel])
elif mode == "ADSR":
adsr1_val = (adsr1_val + 1) % 20
mapped_val = simpleio.map_range(adsr1_val, 0, 19, 0.0, 1.0)
all_adsr_values[1][synth_adsr_indexes[1]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[1][0],
decay_time = all_adsr_values[1][1],
release_time=all_adsr_values[1][3],
attack_level=1, sustain_level=all_adsr_values[1][2])
synth1.envelope = the_env
elif mode == "WAVE":
synth1_wave = (synth1_wave + 1) % len(wave_names)
synth1.waveform = waveforms[synth1_wave]
elif mode == "RING":
ring1_val = (ring1_val + 1) % 25
mapped_val = simpleio.map_range(ring1_val, 0, 24, 0.0, 220.0)
synth1.ring_frequency = mapped_val
else:
if mode == "PLAY":
chord1_sel = (chord1_sel - 1) % len(chords)
display1.print(chord_names[chord1_sel])
elif mode == "ADSR":
adsr1_val = (adsr1_val - 1) % 20
mapped_val = simpleio.map_range(adsr1_val, 0, 19, 0.0, 1.0)
all_adsr_values[1][synth_adsr_indexes[1]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[1][0],
decay_time = all_adsr_values[1][1],
release_time=all_adsr_values[1][3],
attack_level=1, sustain_level=all_adsr_values[1][2])
synth1.envelope = the_env
elif mode == "WAVE":
synth1_wave = (synth1_wave - 1) % len(wave_names)
synth1.waveform = waveforms[synth1_wave]
elif mode == "RING":
ring1_val = (ring1_val - 1) % 25
mapped_val = simpleio.map_range(ring1_val, 0, 24, 0.0, 220.0)
synth1.ring_frequency = mapped_val
last_position1 = position1
if position2 != last_position2:
if position2 > last_position2:
if mode == "PLAY":
chord2_sel = (chord2_sel + 1) % len(chords)
elif mode == "ADSR":
adsr2_val = (adsr2_val + 1) % 20
mapped_val = simpleio.map_range(adsr2_val, 0, 19, 0.0, 1.0)
all_adsr_values[2][synth_adsr_indexes[2]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[2][0],
decay_time = all_adsr_values[2][1],
release_time=all_adsr_values[2][3],
attack_level=1, sustain_level=all_adsr_values[2][2])
synth2.envelope = the_env
elif mode == "WAVE":
synth2_wave = (synth2_wave + 1) % len(wave_names)
synth2.waveform = waveforms[synth2_wave]
elif mode == "RING":
ring2_val = (ring2_val + 1) % 25
mapped_val = simpleio.map_range(ring2_val, 0, 24, 0.0, 220.0)
synth2.ring_frequency = mapped_val
else:
if mode == "PLAY":
chord2_sel = (chord2_sel - 1) % len(chords)
display2.print(chord_names[chord2_sel])
elif mode == "ADSR":
adsr2_val = (adsr2_val - 1) % 20
mapped_val = simpleio.map_range(adsr2_val, 0, 19, 0.0, 1.0)
all_adsr_values[2][synth_adsr_indexes[2]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[2][0],
decay_time = all_adsr_values[2][1],
release_time=all_adsr_values[2][3],
attack_level=1, sustain_level=all_adsr_values[2][2])
synth2.envelope = the_env
elif mode == "WAVE":
synth2_wave = (synth2_wave - 1) % len(wave_names)
synth2.waveform = waveforms[synth2_wave]
elif mode == "RING":
ring2_val = (ring2_val - 1) % 25
mapped_val = simpleio.map_range(ring2_val, 0, 24, 0.0, 220.0)
synth2.ring_frequency = mapped_val
last_position2 = position2
if position3 != last_position3:
if position3 > last_position3:
if mode == "PLAY":
chord3_sel = (chord3_sel + 1) % len(chords)
display3.print(chord_names[chord3_sel])
elif mode == "ADSR":
adsr3_val = (adsr3_val + 1) % 20
mapped_val = simpleio.map_range(adsr3_val, 0, 19, 0.0, 1.0)
all_adsr_values[3][synth_adsr_indexes[3]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[3][0],
decay_time = all_adsr_values[3][1],
release_time=all_adsr_values[3][3],
attack_level=1, sustain_level=all_adsr_values[3][2])
synth3.envelope = the_env
elif mode == "WAVE":
synth3_wave = (synth3_wave + 1) % len(wave_names)
synth3.waveform = waveforms[synth3_wave]
elif mode == "RING":
ring3_val = (ring3_val + 1) % 25
mapped_val = simpleio.map_range(ring3_val, 0, 24, 0.0, 220.0)
synth3.ring_frequency = mapped_val
else:
if mode == "PLAY":
chord3_sel = (chord3_sel - 1) % len(chords)
display3.print(chord_names[chord3_sel])
elif mode == "ADSR":
adsr3_val = (adsr3_val - 1) % 20
mapped_val = simpleio.map_range(adsr3_val, 0, 19, 0.0, 1.0)
all_adsr_values[3][synth_adsr_indexes[3]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[3][0],
decay_time = all_adsr_values[3][1],
release_time=all_adsr_values[3][3],
attack_level=1, sustain_level=all_adsr_values[3][2])
synth3.envelope = the_env
elif mode == "WAVE":
synth3_wave = (synth3_wave - 1) % len(wave_names)
synth3.waveform = waveforms[synth3_wave]
elif mode == "RING":
ring3_val = (ring3_val - 1) % 25
mapped_val = simpleio.map_range(ring3_val, 0, 24, 0.0, 220.0)
synth3.ring_frequency = mapped_val
last_position3 = position3
enc_clock = ticks_add(enc_clock, 100)
# synth plays based on ticks timing
if ticks_diff(ticks_ms(), clock) >= delay:
if play_states[0] is True:
r0, last_r0, c0 = play_euclidean(synth0, chords[chord0_sel],
rhythm0, r0, last_r0, c0, 0)
if play_states[1] is True:
r1, last_r1, c1 = play_euclidean(synth1, chords[chord1_sel],
rhythm1, r1, last_r1, c1, 2)
if play_states[2] is True:
r2, last_r2, c2 = play_euclidean(synth2, chords[chord2_sel],
rhythm2, r2, last_r2, c2, 4)
if play_states[3] is True:
r3, last_r3, c3 = play_euclidean(synth3, chords[chord3_sel],
rhythm3, r3, last_r3, c3, 6)
clock = ticks_add(clock, delay)
# in PLAY select button controls play/pause
if mode == "PLAY":
for i in range(4):
if not select_buttons[i].value and select_states[i] is False:
select_states[i] = True
if play_states[i] is True:
synth.release(synths[i])
play_states[i] = False
else:
play_states[i] = True
if select_buttons[i].value and select_states[i] is True:
select_states[i] = False
display0.print(chord_names[chord0_sel])
display1.print(chord_names[chord1_sel])
display2.print(chord_names[chord2_sel])
display3.print(chord_names[chord3_sel])
# EUC menu select resets cycle count
elif mode == "EUC ":
if not menu_buttons[0].value and menu_states[0] is False:
r0 = 0
r1 = 0
r2 = 0
r3 = 0
menu_states[0] = True
if menu_buttons[0].value and menu_states[0] is True:
menu_states[0] = False
rhythm0, euclid0_steps, euclid0_pulses, r0 = read_buttons(buttons0, button0_states,
rhythm0, euclid0_steps,
euclid0_pulses, r0)
rhythm1, euclid1_steps, euclid1_pulses, r1 = read_buttons(buttons1, button1_states,
rhythm1, euclid1_steps,
euclid1_pulses, r1)
rhythm2, euclid2_steps, euclid2_pulses, r2 = read_buttons(buttons2, button2_states,
rhythm2, euclid2_steps,
euclid2_pulses, r2)
rhythm3, euclid3_steps, euclid3_pulses, r3 = read_buttons(buttons3, button3_states,
rhythm3, euclid3_steps,
euclid3_pulses, r3)
display0.print(f" {euclid0_pulses}")
display1.print(f" {euclid1_pulses}")
display2.print(f" {euclid2_pulses}")
display3.print(f" {euclid3_pulses}")
# BPM is adjusted
elif mode == "BPM ":
if not select_buttons[0].value and select_states[0] is False:
bpm = 120
select_states[0] = True
if select_buttons[0].value and select_states[0] is True:
select_states[0] = False
display0.print(f" {bpm}")
display1.print(" ")
display2.print(" ")
display3.print(" ")
# beat division is changed
elif mode == "BEAT":
if not select_buttons[0].value and select_states[0] is False:
beat_names[beat_index] = 2
select_states[0] = True
if select_buttons[0].value and select_states[0] is True:
select_states[0] = False
display0.print(f" {beat_names[beat_index]}")
display1.print(" ")
display2.print(" ")
display3.print(" ")
# adsr for each voice
elif mode == "ADSR":
for i in range(4):
if not left_buttons[i].value and left_states[i] is False:
synth_adsr_indexes[i] = (synth_adsr_indexes[i] - 1) % 4
left_states[i] = True
the_synth = synths[i]
if left_buttons[i].value and left_states[i] is True:
left_states[i] = False
if not right_buttons[i].value and right_states[i] is False:
synth_adsr_indexes[i] = (synth_adsr_indexes[i] + 1) % 4
right_states[i] = True
if right_buttons[i].value and right_states[i] is True:
right_states[i] = False
if not select_buttons[i].value and select_states[i] is False:
the_synth = synths[i]
all_adsr_values[i][0] = 0.1
all_adsr_values[i][1] = 0.1
all_adsr_values[i][3] = 0.1
all_adsr_values[i][2] = 0.05
the_env = synthio.Envelope(attack_time=all_adsr_values[i][0],
decay_time = all_adsr_values[i][1],
release_time=all_adsr_values[i][3],
attack_level=1, sustain_level=all_adsr_values[i][2])
the_synth.envelope = the_env
select_states[i] = True
if select_buttons[i].value and select_states[i] is True:
select_states[i] = False
# pylint: disable=line-too-long
display0.print(f"{adsr_names[synth_adsr_indexes[0]]}{synth0.envelope[adsr_properties[synth_adsr_indexes[0]]]:.2f}")
display1.print(f"{adsr_names[synth_adsr_indexes[1]]}{synth1.envelope[adsr_properties[synth_adsr_indexes[1]]]:.2f}")
display2.print(f"{adsr_names[synth_adsr_indexes[2]]}{synth2.envelope[adsr_properties[synth_adsr_indexes[2]]]:.2f}")
display3.print(f"{adsr_names[synth_adsr_indexes[3]]}{synth3.envelope[adsr_properties[synth_adsr_indexes[3]]]:.2f}")
# change waveform
elif mode == "WAVE":
display0.print(f" {wave_names[synth0_wave]}")
display1.print(f" {wave_names[synth1_wave]}")
display2.print(f" {wave_names[synth2_wave]}")
display3.print(f" {wave_names[synth3_wave]}")
# adjust ring modulation
elif mode == "RING":
display0.print(f" {synth0.ring_frequency:.1f}")
display1.print(f" {synth1.ring_frequency:.1f}")
display2.print(f" {synth2.ring_frequency:.1f}")
display3.print(f" {synth3.ring_frequency:.1f}")
# adjust lfo rate used for ring modulation
elif mode == "LFO ":
display0.print("RATE")
display1.print(f" {lfo.rate:.1f}")
display2.print(" ")
display3.print(" ")
# overall volume 0.0 - 1.0
elif mode == "VOL ":
display0.print(f" {mixer.voice[0].level:.1f}")
display1.print(" ")
display2.print(" ")
display3.print(" ")
Upload the Code and Libraries to the Feather RP2040
After downloading the Project Bundle, plug your Feather RP2040 into the computer's USB port with a known good USB data+power cable. You should see a new flash drive appear in the computer's File Explorer or Finder (depending on your operating system) called CIRCUITPY. Unzip the folder and copy the following items to the Feather RP2040's CIRCUITPY drive.
- lib folder
- code.py
Your Feather RP2040 CIRCUITPY drive should look like this after copying the lib folder and the code.py file:
How the CircuitPython Code Works
The code begins by creating some waveform and ADSR envelope objects. These objects are passed to synthio.Note objects. There are four Note objects and they will create four different voices.
The Notes are played by the Synthesizer object, which outputs through the Mixer object.
SAMPLE_RATE = 44100
SAMPLE_SIZE = 256
VOLUME = 5000
# waveforms, envelopes and synth setup
square = np.concatenate((np.ones(SAMPLE_SIZE//2, dtype=np.int16)*VOLUME,np.ones(SAMPLE_SIZE//2,
dtype=np.int16)*-VOLUME))
sine = np.array(np.sin(np.linspace(0, 4*np.pi, SAMPLE_SIZE, endpoint=False)) * VOLUME,
dtype=np.int16)
saw = np.linspace(VOLUME, -VOLUME, num=SAMPLE_SIZE, dtype=np.int16)
noise = np.array([randint(-VOLUME, VOLUME) for i in range(SAMPLE_SIZE)], dtype=np.int16)
lfo = synthio.LFO(rate = .5, waveform = sine)
amp_env0 = synthio.Envelope(attack_time=0.1, decay_time = 0.1, release_time=0.1,
attack_level=1, sustain_level=0.05)
amp_env1 = synthio.Envelope(attack_time=0.05, decay_time = 0.1, release_time=0.1,
attack_level=1, sustain_level=0.05)
# synth plays the notes
synth = synthio.Synthesizer(sample_rate=SAMPLE_RATE)
# these are the notes
synth0 = synthio.Note(frequency = 0.0, envelope=amp_env0, waveform=square, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth1 = synthio.Note(frequency = 0.0, envelope=amp_env1, waveform=sine, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth2 = synthio.Note(frequency = 0.0, envelope=amp_env0, waveform=square, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synth3 = synthio.Note(frequency = 0.0, envelope=amp_env1, waveform=sine, ring_frequency = 0,
ring_bend = lfo, ring_waveform = sine)
synths = [synth0, synth1, synth2, synth3]
wave_names = ["SQUR", "SINE", "SAW ", "NOIZ"]
waveforms = [square, sine, saw, noise]
synth0_wave = 0
synth1_wave = 1
synth2_wave = 0
synth3_wave = 1
# i2s amp setup
audio = audiobusio.I2SOut(bit_clock=board.D10, word_select=board.D11, data=board.D9)
mixer = audiomixer.Mixer(voice_count=4, sample_rate=SAMPLE_RATE, channel_count=1,
bits_per_sample=16, samples_signed=True, buffer_size=2048 )
audio.play(mixer)
vol_val = 2
mixer.voice[0].play(synth)
mixer.voice[0].level = 0.3
Tones
Arrays of tones are created for triads. They are all I (tonic) chords in the circle of fifths.
# these are the triads, all major
c_tones = [130.81, 164.81, 196.00]
g_tones = [196.00, 246.94, 293.66]
d_tones = [146.83, 185.00, 220.00]
a_tones = [220.00, 277.18, 329.63]
e_tones = [164.81, 207.65, 246.94]
b_tones = [246.94, 311.13, 369.99]
fsharp_tones = [185.00, 233.08, 277.18]
csharp_tones = [138.59, 174.61, 207.65]
aflat_tones = [207.65, 261.63, 311.13]
eflat_tones = [155.56, 196.00, 233.08]
bflat_tones = [233.08, 293.66, 349.23]
f_tones = [174.61, 220.00, 261.63]
# names for the alphanumeric displays
chord_names = ["Cmaj", "Gmaj", "Dmaj", "Amaj", "Emaj", "Bmaj",
"F#ma", "C#ma", "Abma", "Ebma", "Bbma", "Fmaj"]
chords = [c_tones, g_tones, d_tones, a_tones, e_tones, b_tones, fsharp_tones, csharp_tones,
aflat_tones, eflat_tones, bflat_tones, f_tones]
I2C
Next are the I2C peripherals. There are five ANO rotary encoders, five alphanumeric displays and one 8x8 matrix.
# i2c setup
i2c = board.I2C()
# the encoders
seesaw0 = seesaw.Seesaw(i2c, addr=0x49)
seesaw1 = seesaw.Seesaw(i2c, addr=0x4A)
seesaw2 = seesaw.Seesaw(i2c, addr=0x4B)
seesaw3 = seesaw.Seesaw(i2c, addr=0x4C)
menu_seesaw = seesaw.Seesaw(i2c, addr=0x4D)
# the alphanumeric displays
display0 = segments.Seg14x4(i2c, address=0x70)
display1 = segments.Seg14x4(i2c, address=0x71)
display2 = segments.Seg14x4(i2c, address=0x72)
display3 = segments.Seg14x4(i2c, address=0x73)
menu_display = segments.Seg14x4(i2c, address=0x74)
# the matrix
matrix0 = Matrix8x8x2(i2c, address=0x75)
seesaws = [seesaw0, seesaw1, seesaw2, seesaw3, menu_seesaw]
buttons0 = []
buttons1 = []
buttons2 = []
buttons3 = []
menu_buttons = []
button0_states = []
button1_states = []
button2_states = []
button3_states = []
menu_states = []
button0_names = ["Select", "Up", "Left", "Down", "Right"]
# setup the buttons on all of the encoders
for i in range(1, 6):
seesaw0.pin_mode(i, seesaw0.INPUT_PULLUP)
seesaw1.pin_mode(i, seesaw1.INPUT_PULLUP)
seesaw2.pin_mode(i, seesaw2.INPUT_PULLUP)
seesaw3.pin_mode(i, seesaw3.INPUT_PULLUP)
menu_seesaw.pin_mode(i, menu_seesaw.INPUT_PULLUP)
buttons0.append(digitalio.DigitalIO(seesaw0, i))
buttons1.append(digitalio.DigitalIO(seesaw1, i))
buttons2.append(digitalio.DigitalIO(seesaw2, i))
buttons3.append(digitalio.DigitalIO(seesaw3, i))
menu_buttons.append(digitalio.DigitalIO(menu_seesaw, i))
button0_states.append(False)
button1_states.append(False)
button2_states.append(False)
button3_states.append(False)
menu_states.append(False)
# make all of the encoders
encoder0 = rotaryio.IncrementalEncoder(seesaw0)
last_position0 = 0
encoder1 = rotaryio.IncrementalEncoder(seesaw1)
last_position1 = 0
encoder2 = rotaryio.IncrementalEncoder(seesaw2)
last_position2 = 0
encoder3 = rotaryio.IncrementalEncoder(seesaw3)
last_position3 = 0
menu_enc = rotaryio.IncrementalEncoder(menu_seesaw)
last_menuPosition = 0
Conjunction Function
There are two functions that are used in the loop. The first reads all of the selector encoder buttons to adjust the Euclidean rhythm parameters.
def read_buttons(button_array, button_states, euc, e_step, e_pulse, the_step):
for b in range(5):
if not button_array[b].value and button_states[b] is False:
button_states[b] = True
if button0_names[b] == "Select":
e_step = 8
e_pulse = 4
if the_step >= e_step:
the_step = 0
elif button0_names[b] == "Up":
if e_step > 16:
e_step = 16
else:
e_step += 1
elif button0_names[b] == "Down":
if e_step < 1:
e_step = 1
else:
e_step -= 1
if the_step >= e_step:
the_step = 0
elif button0_names[b] == "Left":
e_pulse -= 1
e_pulse = max(e_pulse, 1)
else:
e_pulse += 1
e_pulse = min(e_pulse, e_step)
euc = bjorklund(e_step, e_pulse)
if button_array[b].value and button_states[b] is True:
button_states[b] = False
if button0_names[b] in ("Select", "Up", "Down"):
matrix0.fill(matrix0.LED_OFF)
draw_steps(euclid0_steps, 0)
draw_steps(euclid1_steps, 2)
draw_steps(euclid2_steps, 4)
draw_steps(euclid3_steps, 6)
return euc, e_step, e_pulse, the_step
The second actually plays the Euclidean rhythms with the passed in chord to the designated synth voice.
def play_euclidean(this_synth, n, the_rhythm, rhythm_count, last_count, c, matrix_slot):
if last_count <= 7:
matrix0[matrix_slot, last_count] = matrix0.LED_GREEN
else:
c -= 1
matrix0[matrix_slot + 1, (last_count - last_count) + c] = matrix0.LED_GREEN
c += 1
if the_rhythm[rhythm_count] == 1:
this_synth.frequency = n[randint(0, 2)]
synth.press(this_synth)
if rhythm_count <= 7:
matrix0[matrix_slot, rhythm_count] = matrix0.LED_RED
else:
matrix0[matrix_slot + 1, (rhythm_count - rhythm_count) + c] = matrix0.LED_RED
c += 1
else:
synth.release(this_synth)
if rhythm_count > 7:
c += 1
last_count = rhythm_count
rhythm_count += 1
if rhythm_count >= len(the_rhythm):
rhythm_count = 0
if rhythm_count == 1:
c = 0
return rhythm_count, last_count, c
ADSR Prep
A few arrays and variables are prepared in order to affect the ADSR envelope for each synth voice. When a change is made to an envelope, a new envelope must be instantiated. These arrays allow you to store the previous ADSR values to pass to this new envelope. As a result, if you change the attack value, the previous decay, sustain and release values are retained and passed to the new envelope.
# adsr mode
adsr_names = ["A", "D", "S", "R"]
synth_adsr_indexes = [0, 0, 0, 0]
adsr_properties = [0, 1, 4, 2]
adsr0_values = [amp_env0.attack_time, amp_env0.decay_time,
amp_env0.sustain_level, amp_env0.release_time]
adsr1_values = [amp_env1.attack_time, amp_env1.decay_time,
amp_env1.sustain_level, amp_env1.release_time]
adsr2_values = [amp_env0.attack_time, amp_env0.decay_time,
amp_env0.sustain_level, amp_env0.release_time]
adsr3_values = [amp_env1.attack_time, amp_env1.decay_time,
amp_env1.sustain_level, amp_env1.release_time]
all_adsr_values = [adsr0_values, adsr1_values, adsr2_values, adsr3_values]
adsr0_val = int(simpleio.map_range(amp_env0.attack_time, 0.0, 1.0, 0, 19))
adsr1_val = int(simpleio.map_range(amp_env0.decay_time, 0.0, 1.0, 0, 19))
adsr2_val = int(simpleio.map_range(amp_env0.sustain_level, 0.0, 1.0, 0, 19))
adsr3_val = int(simpleio.map_range(amp_env0.release_time, 0.0, 1.0, 0, 19))
The Loop
The loop has four tasks happening: reading the rotary encoders, playing the Euclidean rhythms, updating the alphanumeric displays, and reading the encoder buttons.
The rotary encoders are read with a small delay. The menu encoder controls which mode is active. Each of the four other encoders' functionality changes depending on the mode.
if ticks_diff(ticks_ms(), enc_clock) >= 100:
position0 = encoder0.position
position1 = encoder1.position
position2 = encoder2.position
position3 = encoder3.position
menuPosition = menu_enc.position
# menu changes mode
if menuPosition != last_menuPosition:
if menuPosition > last_menuPosition:
mode_index = (mode_index + 1) % len(modes)
else:
mode_index = (mode_index - 1) % len(modes)
if mode in ("EUC ", "ADSR"):
clock_stretch = True
if mode in ("PLAY", "BPM ", "BEAT", "WAVE") and clock_stretch:
clock = ticks_ms()
clock_stretch = False
mode = modes[mode_index]
menu_display.print(f" {mode}")
last_menuPosition = menuPosition
...
if position1 != last_position1:
if position1 > last_position1:
if mode == "PLAY":
chord1_sel = (chord1_sel + 1) % len(chords)
display1.print(chord_names[chord1_sel])
elif mode == "ADSR":
adsr1_val = (adsr1_val + 1) % 20
mapped_val = simpleio.map_range(adsr1_val, 0, 19, 0.0, 1.0)
all_adsr_values[1][synth_adsr_indexes[1]] = mapped_val
the_env = synthio.Envelope(attack_time=all_adsr_values[1][0],
decay_time = all_adsr_values[1][1],
release_time=all_adsr_values[1][3],
attack_level=1,
sustain_level=all_adsr_values[1][2])
synth1.envelope = the_env
elif mode == "WAVE":
synth1_wave = (synth1_wave + 1) % len(wave_names)
synth1.waveform = waveforms[synth1_wave]
...
No matter which mode, the synth plays on; using ticks to keep time. play_states[] keeps track of whether or not a synth voice is paused.
# synth plays based on ticks timing
if ticks_diff(ticks_ms(), clock) >= delay:
if play_states[0] is True:
r0, last_r0, c0 = play_euclidean(synth0, chords[chord0_sel],
rhythm0, r0, last_r0, c0, 0)
if play_states[1] is True:
r1, last_r1, c1 = play_euclidean(synth1, chords[chord1_sel],
rhythm1, r1, last_r1, c1, 2)
if play_states[2] is True:
r2, last_r2, c2 = play_euclidean(synth2, chords[chord2_sel],
rhythm2, r2, last_r2, c2, 4)
if play_states[3] is True:
r3, last_r3, c3 = play_euclidean(synth3, chords[chord3_sel],
rhythm3, r3, last_r3, c3, 6)
clock = ticks_add(clock, delay)
Just like the rotary encoders, the buttons and alphanumeric displays have different functionality depending on the mode. The alphanumeric displays will update to show different values. For example, in Wave mode, the waveform for each voice is displayed. As the waveform is changed with the rotary encoder, the display updates.
# in PLAY select button controls play/pause
if mode == "PLAY":
for i in range(4):
if not select_buttons[i].value and select_states[i] is False:
select_states[i] = True
if play_states[i] is True:
synth.release(synths[i])
play_states[i] = False
else:
play_states[i] = True
if select_buttons[i].value and select_states[i] is True:
select_states[i] = False
display0.print(chord_names[chord0_sel])
display1.print(chord_names[chord1_sel])
display2.print(chord_names[chord2_sel])
display3.print(chord_names[chord3_sel])
...
# change waveform
elif mode == "WAVE":
display0.print(f" {wave_names[synth0_wave]}")
display1.print(f" {wave_names[synth1_wave]}")
display2.print(f" {wave_names[synth2_wave]}")
display3.print(f" {wave_names[synth3_wave]}")
Page last edited January 22, 2025
Text editor powered by tinymce.
