LED Panel
| LED Panel Release status: beta [box doku] | |
|---|---|
| Description | Displays a ticker on the LED Panel in the space |
| Author(s) | Matthias |
The LED Panel actually consists 2 32x128 LED matrixes with a HUB75 connected to a Raspberry Pi 1. The panels are provided by Jorgen, the pi by Matthias The custom software can retrieve messages via MQTT (what else) and display them in two rows. The first row is the "larger" one, the second row the smaller one. The content and format of the text can be heavily customized via MQTT (see below).
Software
- Based on the RPI-RGB-LED-Matrix project from hzeller [1].
- Uses the C++ MQTT Paho library (needs to be compiled and installed to /usr/local/lib & /usr/local/include accordingly)
- The Code is located here https://github.com/siedi/rpi-led-mqtt
- The LED software is automatically launched on startup via the crontab of the pi user and running in the background.
Run it
The program needs to run as root to access the gpios. Without any parameters, it will start with the defaults configured in the source code.
sudo ./led-mqtt
The following command line parameters are available:
| parameter | description |
|---|---|
| -S <xxx> | Set MQTT server |
MQTT topics & commands
The topic structure is <prefix>/<command>/<parameter>, e.g. mumalab/room/ledpanel/set/once1
- prefix: as give by the command line
- command: "set" to set a value. There are currently no other commands implemented (like get)
- parameter: see table below
- payload: the value to set
| topic parameter | description | value example |
|---|---|---|
| text1 | Sets the text of the ticker in the first, upper line. | Welcome to the MuMaLab! |
| text2 | Sets the text of the ticker in the second, lower line. | We love LEDs! |
| once1 | Interrupts the current ticker in the first line and displays this ticker once. Afterward displays the old text1 ticker. | ALARM!!! |
| once2 | Interrupts the current ticker in the second line and displays this ticker once. Afterward displays the old text2 ticker. | Let's go! |
| color1 | The RGB value of the first line, as a string, comma separated. | 255,0,128 |
| color2 | The RGB value of the second line, as a string, comma separated. | 255,0,128 |
| font1 | Name of the font file as on the server for the first text line. | 9x18.bdf |
| font2 | Name of the font file as on the server for the second text line. | 5x8.bdf |
Software Compilation
In case you need to setup a new system and compile the software again, here are some hints.
You might need to install the one or the other Debian package (e.g. build-essential libssl-dev libjsoncpp-dev). You will find out when the compilation fails :-).
- Install the PAHO MQTT libraries:
# Install the c client first git https://github.com/eclipse/paho.mqtt.c cd paho.mqtt.c make sudo make install cd .. git clone https://github.com/eclipse/paho.mqtt.cpp cd paho.mqtt.cpp make sudo make install
- Install led-mqtt:
git clone -recursive https://github.com/siedi/rpi-led-mqtt.git cd rpi-led-mqtt make
