Neopixel Control Server

control-socket.py

#!/usr/bin/env python3

import math
import asyncio
import websockets
import neopixel

# Neo configuration:
LED_COUNT      = 60      # Number of LED pixels.
LED_PIN        = 18      # GPIO pin connected to the pixels (must support PWM!).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 5       # DMA channel to use for generating signal (try 5)
LED_BRIGHTNESS = 100     # Set to 0 for darkest and 255 for brightest
LED_INVERT     = False   # True to invert the signal (when using NPN transistor level shift)

neo = neopixel.Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS)
neo.begin()

def spread(strip, length):
  return list(map(lambda x: strip[math.floor(x / (length / len(strip)))], range(length)));

async def router(websocket, path):
  while True:
    payload = await websocket.recv()
    decoded = payload.split('#')
    command = None
    args = None

    if (len(decoded) == 1):
      command = decoded[0]
      args = ''
    elif (len(decoded) == 2):
      command = decoded[0]
      args = decoded[1]

    if (command == None or command == ''):
      print('Invalid Payload: ', payload)
      continue

    print(command, args)

    # Python WHY U HAZ NO SWITCH
    if command == 'color':
      for led, color in enumerate(spread(args.split(','), LED_COUNT)):
        neo.setPixelColor(led, int(color))
      neo.show()
    elif command == 'brightness':
      neo.setBrightness(int(args))
    elif command == 'clear':
      for led, color in enumerate(spread([0], LED_COUNT)):
        neo.setPixelColor(led, int(color))
      neo.show()
    else:
      print('Command Not Recognised')

start_server = websockets.serve(router, '0.0.0.0', 8765)

asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

DOC.md

Neopixel Control Server

Connection

The control server hosts an RFC-6455 WebSocket on Port 8765. You can use any compliant library or (where supported) the in-built Web Sockets API to connect.

Commands

The control server accepts commands as a string with the following structure:

<$command><#?><$args?>

The following $commands are defined:

• Color e.g. color#16711727,5308671,13631743 Set the color of each pixel to the corrosponding 24bit rgb value*. The values will be spread across the leds if the LED count does not match the amount of values.
• Brightness e.g. brightness#50 Set the LED brightness to the value [0-255] provided. Note: This takes effect on the next use of the Color command.
• Clear e.g. clear Sets all LEDs to 0, effectively turning them off.

Notes

• (*) To create a 24bit rgb value in most languages: (red << 8) | (green << 16) | blue