Improving MIDI arpeggiator. LEDs show current note now. Documentation.

examples/colour-picker.py

@@ -5,6 +5,8 @@
 # This example demonstrates the use of a modifier key to pick the colour of the 
 # keys' LEDs, as well as the LED sleep functionality.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 import time
 import board
 import random

examples/decorators.py

@@ -5,6 +5,8 @@
 # This example demonstrates attaching functions to keys using decorators, and
 # the ability to turn the LEDs off with led_sleep_enabled and led_sleep_time.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 import time
 import board
 import random

examples/midi-arp.py

@@ -2,12 +2,15 @@
 #
 # SPDX-License-Identifier: MIT
 
-# Demonstrates how to send MIDI notes by attaching handler functions to key
-# presses with decorators.
+# A MIDI arpeggiator, with three different styles: up, down, or up-down. BPM and
+# note length are both configurable, and LEDs cycle with the currently-played
+# key/note to give some visual feedback.
 
 # You'll need to connect Keybow 2040 to a computer running a DAW like Ableton,
 # or other software synth, or to a hardware synth that accepts USB MIDI.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 # NOTE! Requires the adafruit_midi CircuitPython library!
 
 import time
@@ -28,90 +31,124 @@ keys = keybow.keys
 # Set USB MIDI up on channel 0.
 midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=5)
 
-# The colour to set the keys when pressed.
+# The colour to set the keys when pressed, orange-y.
 rgb = (255, 50, 0)
 
 # MIDI velocity.
 start_note = 60
-velocity = 127
+velocity = 100
+
+# Beats per minute
+bpm = 120
+
+# Play 16th notes
+note_length = 1/16
+
+# Assumes BPM is calculated on quarter notes
+note_time = 60 / bpm * (note_length * 4)
 
 # Arpeggio style:
 # 0 = up
 # 1 = down
-# 2 = up down
+# 2 = up-down
 arp_style = 2
 
+# Start the arp in a forwards direction (1) if the style is up or up-down, or
+# or backwards (-1) if the style is down.
 if arp_style == 0 or arp_style == 2:
     direction = 1
 elif arp_style == 1:
     direction = -1
 
+# Keep track of time of last note played and last keys pressed
 last_played = None
 last_pressed = []
-speed = 5
-
-# Loop through keys and attach decorators.
-for key in keys:
-    # If pressed, turn on LED.
-    @keybow.on_press(key)
-    def press_handler(key):
-        key.set_led(*rgb)
-
-    # If released, turn off LED.
-    @keybow.on_release(key)
-    def release_handler(key):
-        key.set_led(0, 0, 0)
 
 while True:
     # Always remember to call keybow.update()!
     keybow.update()
 
+    # If any keys are pressed, go through shenanigans
     if keybow.any_pressed():
+        # Fetch a list of pressed keys
         pressed = keybow.get_pressed()
 
+        # If the keys pressed have changed...
         if pressed != last_pressed:
+            # Keys that were pressed, but are no longer
+            missing = [k for k in last_pressed if k not in pressed]
+
+            # Any keys that were pressed, but are no longer, turn LED off
+            # and send MIDI note off for the respective note.
+            for k in missing:
+                note = start_note +k
+                midi.send(NoteOff(note, 0))
+                keys[k].set_led(0, 0, 0)
+
+            # Calculate MIDI note numbers
             notes = [start_note + k for k in pressed]
             last_pressed = pressed
 
+            # If going forward (up or starting up-down), start at 0,
+            # otherwise start at the end of the list of notes.
             if arp_style == 0 or arp_style == 2:
                 this_note = 0
             elif arp_style == 1:
                 this_note = len(notes) - 1
 
+            # Send MIDI note on message for current note and turn LED on
             midi.send(NoteOn(notes[this_note], velocity))
-            print(notes[this_note])
+            keys[pressed[this_note]].set_led(*rgb)
 
+            # Update last_played time, set elapsed to 0, and update current and
+            # last note indices.
             last_played = time.monotonic()
             elapsed = 0
             last_note = this_note
             this_note += direction
 
+        # If the currently pressed notes are the same as the last loop, then...
         else:
             if notes != []:
+                # Check time elapsed since last note played
                 elapsed = time.monotonic() - last_played
 
-                if elapsed > 1 / speed:
+                # If the note time has elapsed, then...
+                if elapsed > note_time:
+                    # Reset at the end or start of the notes list
                     if this_note == len(notes) and direction == 1:
                         this_note = 0
                     elif this_note < 0:
                         this_note = len(notes) - 1
 
+                    # Send a MIDI note off for the last note, turn off LED
                     midi.send(NoteOff(notes[last_note], 0))
-                    midi.send(NoteOn(notes[this_note], velocity))
-                    print(notes[this_note])
+                    keys[pressed[last_note]].set_led(0, 0, 0)
 
+                    # Send a MIDI note on for the next note, turn on LED
+                    midi.send(NoteOn(notes[this_note], velocity))
+                    keys[pressed[this_note]].set_led(*rgb)
+
+                    # Update time last_played, make this note last note
                     last_played = time.monotonic()
                     last_note = this_note
 
+                    # For the up-down style, switch direction at either end
                     if arp_style == 2 and this_note == len(notes) -1:
                         direction = -1
                     elif arp_style == 2 and this_note == 0:
                         direction = 1
 
+                    # Increment note
                     this_note += direction
 
+    # If nothing is now pressed, but was last time, then send MIDI  note off
+    # for every note, and turn all the LEDs off.
     elif len(last_pressed) and keybow.none_pressed():
         for note in range(128):
             midi.send(NoteOff(note, 0))
+        for key in keys:
+            key.set_led(0, 0, 0)
 
+        # Nothing is pressed, so reset last_pressed list
         last_pressed = []

examples/midi-keys.py

@@ -8,6 +8,8 @@
 # You'll need to connect Keybow 2040 to a computer running a DAW like Ableton,
 # or other software synth, or to a hardware synth that accepts USB MIDI.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 # NOTE! Requires the adafruit_midi CircuitPython library!
 
 import time

examples/rainbow.py

@@ -4,6 +4,8 @@
 
 # This example displays a rainbow animation on Keybow 2040's keys.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 import time
 import math
 import board

examples/reactive-press.py

@@ -4,6 +4,8 @@
 
 # This example demonstrates how to light keys when pressed.
 
+# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
+
 import board
 from keybow2040 import Keybow2040
 

keybow2040.py

@@ -8,6 +8,7 @@
 
 CircuitPython driver for the Pimoroni Keybow 2040.
 
+Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
 
 * Author: Sandy Macdonald