Files
lamatrix/raspberrypihal.py
Noah bb67ca9060 Basic support for driving a display with rpi_ws281x
NOTE: weatherscene.py is known to NOT work under Python 3.x due to
an incompatibility with MicroPython's handling of strings and bytes.

This can be easily resolved although I opted to not do this, to preserve
compabilitity with the original code.

To use this on a Raspberry Pi, try:

    sudo apt install -y python-pip python-requests
    sudo pip install rpi_ws281x

Then connect the display's data line to the Raspberry Pi's GPIO 18 (PCM CLK)
(see https://pinout.xyz/)

References:

- https://github.com/noahwilliamsson/lamatrix/issues/1
- https://github.com/rpi-ws281x/rpi-ws281x-python (userspace WS281x driver)
- https://github.com/jgarff/rpi_ws281x (wiring docs)
2021-01-06 14:27:02 +01:00

59 lines
2.0 KiB
Python

# HAL for Raspberry Pi with https://github.com/rpi-ws281x/rpi-ws281x-python
# See https://github.com/jgarff/rpi_ws281x for more details on this library.
#
# The below code assumes the LED strip is connected to GPIO 18 (PCM CLK)
# (see https://pinout.xyz) and that you've installed the rpi_ws281x library.
#
# For Python 2.x:
#
# sudo apt install -y python-pip; sudo pip install rpi_ws281x
#
# For Python 3.x:
#
# sudo apt install -y python3-pip; sudo pip3 install rpi_ws281x
#
#
from rpi_ws281x import PixelStrip, Color
# LED strip configuration:
LED_PIN = 18 # GPIO pin connected to the pixels (18 uses PWM!).
# LED_PIN = 10 # GPIO pin connected to the pixels (10 uses SPI /dev/spidev0.0).
LED_FREQ_HZ = 800000 # LED signal frequency in hertz (usually 800khz)
LED_DMA = 10 # DMA channel to use for generating signal (try 10)
LED_BRIGHTNESS = 255 # Set to 0 for darkest and 255 for brightest
LED_INVERT = False # True to invert the signal (when using NPN transistor level shift)
LED_CHANNEL = 0 # set to '1' for GPIOs 13, 19, 41, 45 or 53
class RaspberryPiHAL:
def __init__(self, config):
self.num_pixels = config['LedMatrix']['columns'] * config['LedMatrix']['stride']
self.strip = PixelStrip(self.num_pixels, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL)
self.strip.begin()
def init_display(self, num_pixels=64):
self.clear_display()
def clear_display(self):
c = Color(0, 0, 0)
for i in range(self.num_pixels):
self.strip.setPixelColor(i, c)
self.strip.show()
def update_display(self, num_modified_pixels):
if not num_modified_pixels:
return
self.strip.show()
def put_pixel(self, addr, r, g, b):
self.strip.setPixelColor(addr % self.num_pixels, Color(r, g, b))
def reset(self):
self.clear_display()
def process_input(self):
#TODO: implement
return 0
def set_rtc(self, t):
#Not relevant
pass
def set_auto_time(self, enable=True):
#Not relevant
pass
def suspend_host(self, restart_timeout_seconds):
#Not relevant
pass