Code the Circuit Playground Express

You'll program your ornament to change colors based on the numbered buttons on the IR mini remote control by using CircuitPython. 

Get Ready!

First, make sure you're up and running by following these steps:

Lighting up the NeoPixel ring in different colors is simple to do on the Circuit Playground Express using CircuitPython. In fact, it only takes a single line of code to make them all bright red: pixels.fill(255, 0, 0) will do the trick in the case of our program! 

To control which colors we see, we can use can use the IR remote control along with IR library that makes it easy to decode the IR commands.

IR commands are actually messages that are sent by the remote when it blinks its infrared light rapidly with very precise timing and duration. It's a little bit like Morse code in that sense. 

Using its IR sensor, the Circuit Playground Express can decode those messages sent by the remote. For more details on how this works, check out this great IR sensor guide.

So that you don't need to deal with the low level complexities of the decoding process, the Adafruit IRRemote library makes it simple!

Download the Remote Tree Ornament Code

Copy the code below, and paste it into a new text document in your text editor, or in the Mu code editor for CircuitPython.

import adafruit_irremote
import board
import digitalio
import neopixel
import pulseio

pixels = neopixel.NeoPixel(board.NEOPIXEL, 10)

red_led = digitalio.DigitalInOut(board.D13)
red_led.direction = digitalio.Direction.OUTPUT

pulsein = pulseio.PulseIn(board.REMOTEIN, maxlen=120, idle_state=True)
decoder = adafruit_irremote.GenericDecode()

# among others, this example works with the Adafruit mini IR remote:
# https://www.adafruit.com/product/389
# size must match what you are decoding! for NEC use 4
received_code = bytearray(4)

# IR Remote Mapping
'''
 1: [255, 2, 247, 8]
 2: [255, 2, 119, 136]
 3: [255, 2, 183, 72]
 4: [255, 2, 215, 40]
 5: [255, 2, 87, 168]
 6: [255, 2, 151, 104]
 7: [255, 2, 231, 24]
 8: [255, 2, 103, 152]
 9: [255, 2, 167, 88]
 0: [255, 2, 207, 48]

^ : [255, 2, 95, 160]
v : [255, 2, 79, 176]
> : [255, 2, 175, 80]
< : [255, 2, 239, 16]

Enter: [255, 2, 111, 144]
Setup: [255, 2, 223, 32]
Stop/Mode: [255, 2, 159, 96]
Back: [255, 2, 143, 112]

Vol - : [255, 2, 255, 0]
Vol + : [255, 2, 191, 64]

Play/Pause: [255, 2, 127, 128]
'''

RED = (255, 0, 0)
GREEN = (0, 255, 0)
WHITE = (85, 85, 85)
BLUE = (0, 0, 255)
PINK = (128, 0, 128)
YELLOW = (148, 108, 0)
PURPLE = (200, 0, 55)
TEAL = (0, 200, 100)
ORANGE = (100, 45, 0)
BLACK = (0, 0, 0)

last_command = None

while True:
    red_led.value = False
    try:
        pulses = decoder.read_pulses(pulsein)
    except MemoryError as e:
        print("Memory error: ", e)
        continue
    red_led.value = True
    print("Heard", len(pulses), "Pulses:", pulses)
    command = None
    try:
        code = decoder.decode_bits(pulses, debug=False)
        if len(code) > 3:
            command = code[2]
        print("Decoded:", code)
    except adafruit_irremote.IRNECRepeatException:  # unusual short code!
        print("NEC repeat!")
        command = last_command
    except adafruit_irremote.IRDecodeException as e:  # failed to decode
        print("Failed to decode:", e)
    except MemoryError as e:
        print("Memory error: ", e)

    if not command:
        continue
    last_command = command

    print("----------------------------")
    red_led.value = False

    if command == 247:  # IR button 1
        pixels.fill(RED)
    elif command == 119:  # 2
        pixels.fill(GREEN)
    elif command == 183:  # 3
        pixels.fill(WHITE)
    elif command == 215:  # 4
        pixels.fill(BLUE)
    elif command == 87:  # 5
        pixels.fill(PINK)
    elif command == 151:  # 6
        pixels.fill(YELLOW)
    elif command == 231:  # 7
        pixels.fill(PURPLE)
    elif command == 103:  # 8
        pixels.fill(TEAL)
    elif command == 167:  # 9
        pixels.fill(ORANGE)
    elif command == 207:
        pixels.fill(BLACK)  # 0/10+

Now, save the code onto your Circuit Playground Express as main.py

The board will restart once the code has been saved. Now, point the remote at the board and press any number button 1-9. See how the lights change color depending on the button!

Code Tour

Let's have a look at how the code works. 

First, we import a few libraries that give us easy commands to use for more complex tasks.

The code blocks that follow are for explanation only, you won't need to use them by themselves, instead use the full code above.
Download: file
import adafruit_irremote
import board
import digitalio
import neopixel
import pulseio

Next, we'll do a bit of setup, creating the NeoPixel object named pixels, and the on-board indicator LED called red_led.

Download: file
pixels = neopixel.NeoPixel(board.NEOPIXEL, 10)

red_led = digitalio.DigitalInOut(board.D13)
red_led.direction = digitalio.Direction.OUTPUT

To prepare the IR pulse detection and decoding, we'll initialize these objects:

Download: file
pulsein = pulseio.PulseIn(board.REMOTEIN, maxlen=120, idle_state=True)
decoder = adafruit_irremote.GenericDecode()

Next, we'll create a variable to store the decoded message number list:

Download: file
received_code = bytearray(4)

Messages

The messages will be sets of four numbers. Here's a list of which buttons correlate to these messages. We'll use this later in the code to know which button has been pressed.

Download: file
# IR Remote Mapping
'''
 1: [255, 2, 247, 8]
 2: [255, 2, 119, 136]
 3: [255, 2, 183, 72]
 4: [255, 2, 215, 40]
 5: [255, 2, 87, 168]
 6: [255, 2, 151, 104]
 7: [255, 2, 231, 24]
 8: [255, 2, 103, 152]
 9: [255, 2, 167, 88]
 0: [255, 2, 207, 48]

^ : [255, 2, 95, 160]
v : [255, 2, 79, 176]
> : [255, 2, 175, 80]
< : [255, 2, 239, 16]

Enter: [255, 2, 111, 144]
Setup: [255, 2, 223, 32]
Stop/Mode: [255, 2, 159, 96]
Back: [255, 2, 143, 112]

Vol - : [255, 2, 255, 0]
Vol + : [255, 2, 191, 64]

Play/Pause: [255, 2, 127, 128]
'''
Note that CircuitPython code that is only meant for humans to read are commented out with the pound # symbol for individual lines, and three single quotes ''' around blocks.

Color Names

Next, we'll create a few variables that make it easier to call out colors by name. The colors of the NeoPixels are described with red, green, and blue values from 0-255.

Download: file
RED = (255, 0, 0)
GREEN = (0, 255, 0)
WHITE = (85, 85, 85)
BLUE = (0, 0, 255)
PINK = (128, 0, 128)
YELLOW = (148, 108, 0)
PURPLE = (200, 0, 55)
TEAL = (0, 200, 100)
ORANGE = (100, 45, 0)
BLACK = (0, 0, 0)

We'll also create a variable to store the value of the last command decoded from the remote, so that we can compare commands to the previous one to know if anything has to change.

Download: file
last_command = None

Main Loop

Now we get to the main loop that runs over and over after the line:

while True:

The first thing we do is turn the red LED off. This way, when an IR command is received later, the LED can be turned on to indicate this. In the absence of that, the LED will turn back off.

red_led.value = False

This next section is where the IR pulses are detected, and then tested to see if they conform to the expected protocol. If so, the decoded pulses are turned into a message we can use.

Download: file
    try:
        pulses = decoder.read_pulses(pulsein)
    except MemoryError as e:
        print("Memory error: ", e)
        continue
    red_led.value = True
    print("Heard", len(pulses), "Pulses:", pulses)
    command = None
    try:
        code = decoder.decode_bits(pulses, debug=False)
        if len(code) > 3:
            command = code[2]
        print("Decoded:", code)
    except adafruit_irremote.IRNECRepeatException:  # unusual short code!
        print("NEC repeat!")
        command = last_command
    except adafruit_irremote.IRDecodeException as e:     # failed to decode
        print("Failed to decode:", e)
    except MemoryError as e:
        print("Memory error: ", e)

    if not command:
        continue
    last_command = command

    print("----------------------------")
    red_led.value = False

Color Commands

Lastly, we'll check the received commands against a list -- if the command corresponds to one of them, the code to change the NeoPixel colors is run.

Download: file
    if command == 247:  # IR button 1
        pixels.fill(RED)
    elif command == 119:  # 2
        pixels.fill(GREEN)
    elif command == 183:  # 3
        pixels.fill(WHITE)
    elif command == 215:  # 4
        pixels.fill(BLUE)
    elif command == 87:  # 5
        pixels.fill(PINK)
    elif command == 151:  # 6
        pixels.fill(YELLOW)
    elif command == 231:  # 7
        pixels.fill(PURPLE)
    elif command == 103:  # 8
        pixels.fill(TEAL)
    elif command == 167:  # 9
        pixels.fill(ORANGE)
    elif command == 207:
        pixels.fill(BLACK)  # 0/10+

Next, we'll build the ornament and use it!

This guide was first published on Dec 24, 2017. It was last updated on Dec 24, 2017. This page (Code the Circuit Playground Express) was last updated on Aug 09, 2019.