Neopixel based XY Matrix running via Raspberry Pi to display time, weather, and news.
- Raspberry Pi
- Neopixel strips (144 leds/m recommended). Get it from either Adafruit or much cheaper options at AliExpress (search for "ws2812b led strips")
- Any Linux based OS running on Raspberry Pi
- Python
- rpi_ws281x library. Tutorial on using: https://learn.adafruit.com/neopixels-on-raspberry-pi/overview
# TL;DR for installing rpi_ws281x library
# install pip if not installed
$ sudo apt install python3-pip
# install libraries
$ sudo pip3 install rpi_ws281x adafruit-circuitpython-neopixel
Before running, there are few modifications to the code you might have to do:
- in
neopixelwrapper.py:- modify the
LED_COUNT,LED_PIN, andLED_ORDERvariables - modify
matrix_to_arrayfunction to match the layout of the neopixel matrix
- modify the
- in
whiterabbit.py:- modify
MATRIX_ROWS,MATRIX_COLSto match rows and columns of pixel in the matrix - modify
RPI_HOSTNAMEto match the hostname the code is running on. otherwise it'll emulate the matrix on terminal
- modify
Once everything is set, as root run:
./run.sh
However, before doing that, read how to build the matrix, connect it to Raspberry Pi, and adjust the settings below.
The leds are arranged this "serpentine" way:
x - x - x - x - x - x - x --- to raspberry pi
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x - x - x - x - x - x - x
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x - x - x - x - x - x - x
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x - x - x - x - x - x - x
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x - x - x - x - x - x - x
If five strips of neopixels with 144 pixels/m are arranged in this way, the pixel numberings will be as follows:
143 - x - x - x - x - x -- 0 --- to raspberry pi
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144 - x - x - x - x - x - 287
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431 - x - x - x - x - x - 288
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432 - x - x - x - x - x - 575
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719 - x - x - x - x - x - 576
The 5V and GND pins from the strip can be connected to any 5V and GND pin of Raspberry Pi. If there are lots of pixels and you are planning to use the full brightness, you need to connect it to external power source with higher amp.
The data pin is connected to any GPIO pin with PWM (18 by default).
See https://learn.adafruit.com/adafruit-neopixel-uberguide for more details about connection and best practices.
BDF font files are used to read data for each character. Modify the values in whiterabbit.py to specify the font file. The MatrixBuffer class is used to construct the buffer before sending the data to the neopixel strip. The NeopixelWrapper::matrix_to_array() converts the matrix to serial data. If the strips are arranged in a different way than described above, this function has to be adjusted to change the mapping.
MatrixBuffer has helper functions to display character text or character.
By default, the current time and weather condition is displayed.
The program also reads fifo file at /tmp/matrix.fifo. If any line of text is written to it, e.g., echo 'Hello, World! This is a scrolling test' > /tmp/matrix.fifo, the text is scrolled on the display. Once the scroll is done, it goes back to displaying time and weather.
Weather data is from National Weather Service. The forecast and current conditions data for a given lat/lon location can be retrieved in json format (among several others).
Air quality data is from Airnow.gov.
The data is retrieved and stored to a file on disk via cron job. Cron jobs look something like this (replace lat and lon data appropriately)
# weather data, every hour
0 * * * * curl 'https://forecast.weather.gov/MapClick.php?lat=37.7771&lon=-122.4196&unit=0&lg=english&FcstType=json' > /var/cache/forecast.json
# airnow data, every hour
0 * * * * curl --data 'latitude=37.7771&longitude=-122.4196&stateCode=CA&maxDistance=50' https://airnowgovapi.com/reportingarea/get > /var/cache/airnow.json
It's Neopixel Matrix, so it's got to have some reference to the movie.