Running an LED Dot Matrix 8x32 (MAX7219) on Diet Pi


Since my discovery of DietPi OS, I have moved pretty much every RPi that I own to this awesome OS, although I will admit that I have found some difficulty when setting up certain hardware, or installing certain software under the OS. BUT, but, but, with the excellent support from the folks on this forum (along with hours of Google Searching) I usually come out with a polished project.

Enter the LED Dot Matrix issue…

I have very little experience with Python, however I am not new to coding in general (HTML, CSS, etc.) and can usually figure my way through a script without a problem. With that said, I embarrassingly admit that I cannot figure out how to get this LED Dot Matrix to work with DietPi OS. As a side note, I am absolutely dumbfounded by the sheer amount of Python Libraries out there. :rofl:

Anyway, here is a link to the LED Dot Matrix that I purchased on Amazon: GeeekPi 2Pack MAX7219 8 x 32 Dot Matrix MCU 4 in 1 LED Display Module for Raspberry Pi (Red)

From my understanding, the MAX7219 is fairly simple to use and install, but again, I just can’t seem to get it working.

So, my goals are as follows:

  1. This particular LED Matrix is made up of four 8x8 LED squares (see pictures below), and I would like to use one of those squares to display the temperate of a Pi that I currently have setup on DietPi - while I do not know if using just one of these squares is ‘doable’, I am willing to use all of them (since item came with two of these 8x32 matrices) daisy chained together since that is how it came packaged.
  2. I would also like to have one (8x8) or all (8x32) display Pi-Hole stats - specifically, just the “Percent Blocked”. If it is easy enough, I wouldn’t mind having it display all of the three main stats (Total Queries + Queries Blocked + Percent Blocked) that Pi-Hole presents on it’s web GUI, but that is absolutely not a ‘must’.
  3. If none of the above are ‘doable’, a simple date/time display also would be cool :sunglasses: (or if anyone has any creative ideas, I am always open to them).

After about an hour of Google searching for a guide or tutorial on how to get this up and running, I only found one decently descriptive website containing some documentation around getting this setup, BUT it does not go into specifics on displaying CPU Temp and/or Pi-Hole Stats. So, I am here, once again, asking for help! :wink:

Any assistance with the setup of the device, the Python Library, as well as the actual display of the above items would be greatly appreciated!

Based on the tutorial, which mixes Python 2 and Python 3 installs/commands somehow, try it like that:

dietpi-software install 130 # installs Python 3 development libraries and pip
apt install build-essential libfreetype6-dev libjpeg-dev libopenjp2-7 libtiff5 # installs the other build dependencies
pip3 install -U luma.led_matrix # installs the LED matrix driver
cd /tmp
curl -sSfLO
tar xf master.tar.gz
rm master.tar.gz
mv luma.led_matrix-master /mnt/dietpi_userdata/luma.led_matrix
cd /mnt/dietpi_userdata/luma.led_matrix
python3 examples/