Display Hat Mini installed but black screen

Support
1

Hi,
(I’m back and hopefully with a little time to take it where I left it).
I installed the Display on a pi 3 on Bullseye 32 with desktop. I have tried on a Pi Zero V1.2 and a Pi Zero 2W but without luck.
On the Pi 3 I got further than on the Zero boards. I got the whole thing installed via Pip3, nevertheless, I had warning just at the end of the installation:

WARNING: The scripts f2py and numpy-config are installed in ‘/home/fern/.local/bin’ which is not on PATH.
Consider adding this directory to PATH

I googled it but the instructions I found were for other OS and wasn’t sure how to proceed.
Anyone can help me finding my path in Pi (and getting the scripts to their right place)?
Thank you very much.

2

I found this on the Pi forums:

PATH=$PATH:/home/pi/.local/bin

to add to PATH.but no result.
Is that the correct order to add /home/fern/.local/bin to PATH?
If it is, why I still have a black screen on the Display Hat Mini?
Any ideas?
Thank you

3

I had another attempt to re-install the display hat mini.

It went well with no warnings but showed this:

Installing collected packages: gpiod, spidev, numpy, gpiodevice, st7789, displayhatmini
Attempting uninstall: spidev
Found existing installation: spidev 3.5
Not uninstalling spidev at /usr/lib/python3/dist-packages, outside environment /usr
Can’t uninstall ‘spidev’. No files were found to uninstall.
Attempting uninstall: numpy
Found existing installation: numpy 1.19.5
Not uninstalling numpy at /usr/lib/python3/dist-packages, outside environment /usr
Can’t uninstall ‘numpy’. No files were found to uninstall.
Successfully installed displayhatmini-0.0.2 gpiod-2.2.2 gpiodevice-0.0.5 numpy-2.0.2 spidev-3.6 st7789-1.0.1
Done!

If I try to run any of the examples this is what I get:
python3 pwm-backlight.py
Traceback (most recent call last):
File “/home/fern/.local/lib/python3.9/site-packages/numpy/_core/init.py”, line 23, in
from . import multiarray
File “/home/fern/.local/lib/python3.9/site-packages/numpy/_core/multiarray.py”, line 10, in
from . import overrides
File “/home/fern/.local/lib/python3.9/site-packages/numpy/_core/overrides.py”, line 8, in
from numpy._core._multiarray_umath import (
ImportError: libopenblas.so.0: cannot open shared object file: No such file or directory

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “/home/fern/.local/lib/python3.9/site-packages/numpy/init.py”, line 114, in
from numpy.config import show as show_config
File “/home/fern/.local/lib/python3.9/site-packages/numpy/config.py”, line 4, in
from numpy._core._multiarray_umath import (
File “/home/fern/.local/lib/python3.9/site-packages/numpy/_core/init.py”, line 49, in
raise ImportError(msg)
ImportError:

IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!

Importing the numpy C-extensions failed. This error can happen for
many reasons, often due to issues with your setup or how NumPy was
installed.

We have compiled some common reasons and troubleshooting tips at:

https://numpy.org/devdocs/user/troubleshooting-importerror.html

Please note and check the following:

  • The Python version is: Python3.9 from “/usr/bin/python3”
  • The NumPy version is: “2.0.2”

and make sure that they are the versions you expect.
Please carefully study the documentation linked above for further help.

Original error was: libopenblas.so.0: cannot open shared object file: No such file or directory

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File “/home/fern/Pimoroni/displayhatmini/examples/pwm-backlight.py”, line 3, in
from displayhatmini import DisplayHATMini
File “/home/fern/.local/lib/python3.9/site-packages/displayhatmini/init.py”, line 2, in
from ST7789 import ST7789
File “/home/fern/.local/lib/python3.9/site-packages/ST7789.py”, line 3, in
from st7789 import * # noqa F403
File “/home/fern/.local/lib/python3.9/site-packages/st7789/init.py”, line 26, in
import numpy
File “/home/fern/.local/lib/python3.9/site-packages/numpy/init.py”, line 119, in
raise ImportError(msg) from e
ImportError: Error importing numpy: you should not try to import numpy from
its source directory; please exit the numpy source tree, and relaunch
your python interpreter from there.

4

Finally, after the nth attempt, it worked. I needed to follow some of the instructions on:

https://numpy.org/devdocs/user/troubleshooting-importerror.html

Make sure you have python3-PIP installed and that IPS and i2c are enabled on raspi-config.
Installing via pip3 install was problematic, coming up with warnings about environments and files not on path. I did try their solution to put f2py and numpy on PATH but it didn’t work.
After another fresh installation (OS image and library), following instructions on Troubleshooting — NumPy v2.3.dev0 Manual I uninstalled numpy

pip3 uninstall numpy

and re-installed via apt install python3-numpy.
Finally I upgraded pygame

python3 -m pip install pygame --upgrade

to be able to run the examples and it finally it worked.
Next I will try to make a kiosk of the Pi2w with the DMH as sole display.
I’m sure I will be back here asking for advice.