Raspberry Pi Zero 2W + 0.91 inch OLED (SSD1306)

Playing with this cheap OLED display:

Size: 0.91 inch

Resolution: 128 x 32 pixels

Interface: I2C

Operating voltage: 3.3 V~5V
 

Update the system once:

$ sudo apt update
$ sudo apt upgrade -y

$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 12 (bookworm)
Release: 12
Codename: bookworm

$ uname -a
Linux pizero2w 6.12.25+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.25-1+rpt1 (2025-04-30) aarch64 GNU/Linux

Setup I2C for Raspi

$ sudo raspi-config → then enable I2C communication from "Interface Options" menu

$ sudo reboot

Install I2C utilities

$ sudo apt install i2c-tools

Connect the display to raspi

Display GND →  Raspi GND pin no.5

Display VCC →  Raspi 3V pin no.1

Display SDA  →  Raspi pin no.2

Display SCK  →  Raspi pin no.3

Check if Raspi can detect the display 

$ i2cdetect -y 1 → this command should show "0x3C" address

Install the following packages for python environment:

$ sudo apt install python3-pip
$ sudo apt install python3-venv

Create python virtual environment

$ mkdir $HOME/ws_py
$ cd $HOME/ws_py && python -m venv .venv

Activate python virtual environment (current working directory is $HOME/ws_py)

$ . .venv/bin/activate
(.venv) ~/ws_py $

After python virtual environment is activated, install python packages using pip

$ pip install Pillow

$ pip install RPi.GPIO

$ pip install adafruit-circuitpython-ssd1306

$ pip install adafruit-blinka

Check if the display is working properly using example code from Adafruit

$ cd $HOME/ws_py

$ git clone https://github.com/adafruit/Adafruit_CircuitPython_SSD1306.git

$ cd examples

$ python ssd1306_stats.py

The display should show the IP address, CPU, memory and disk info of the raspberry pi after this step

Selenium on nethunter (pixel)

Make sure firefox is installed

$ firefox -V
Mozilla Firefox 115.5.0esr

Download geckodriver

$ wget https://github.com/mozilla/geckodriver/releases/download/v0.34.0/geckodriver-v0.34.0-linux-aarch64.tar.gz
$ tar xzvf geckodriver-v0.34.0-linux-aarch64.tar.gz

After this step "geckodriver" should be there

$ ./geckodriver -V
geckodriver 0.34.0 (c44f0d09630a 2024-01-02 15:36 +0000)
The source code of this program is available from testing/geckodriver in https://hg.mozilla.org/mozilla-central.
This program is subject to the terms of the Mozilla Public License 2.0. You can obtain a copy of the license
at https://mozilla.org/MPL/2.0/

Install 'selenium'

$ pip3 install selenium

Test code

import os
import sys
import logging
from selenium import webdriver
from selenium.webdriver.firefox.service import Service


THIS_DIR = os.path.dirname(os.path.abspath(__file__))
DRIVER = os.path.join(THIS_DIR, "geckodriver-v0.34.0-linux-aarch64", "geckodriver")

if not os.path.exists(DRIVER):
    print("Cannot find 'geckodriver'")
    sys.exit(1)


def main():
    print("Downloading web page...")

    s = Service(executable_path=DRIVER)

    options = webdriver.FirefoxOptions()
    options.add_argument("--headless")

    driver = webdriver.Firefox(service=s, options=options)
    
    driver.get("https://www.google.com")
    driver.save_screenshot("screenshot.png")

    print("Please check screenshot image")
    driver.quit()


if __name__ == '__main__':
    main()

After run this code "screenshot.png" should be generated

To show "screenshot.png" image in RLogin

$ sudo apt install libsixel-bin
$ img2sixel screenshot.png

Done.

How to fix error: No module named 'apt_pkg' on Ubuntu 18.04

 Ubuntu 18.04 has python3.6.x installed but after install python3.8 and used "update-alternatives" to change the default python3 to python3.8, got the following error when running unknown command on the terminal

$ dummyyycommand  
    from CommandNotFound import CommandNotFound
  File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 19, in
    from CommandNotFound.db.db import SqliteDatabase
  File "/usr/lib/python3/dist-packages/CommandNotFound/db/db.py", line 5, in
    import apt_pkg
ModuleNotFoundError: No module named 'apt_pkg'

This is caused because python3.8 cannot load "apt_pkg.cpython-36m-x86_64-linux-gnu.so"

$ cd /usr/lib/python3/dist-packages; ls -al | grep apt
drwxr-xr-x   4 root root   4096 Mar  3 22:23 apt
drwxr-xr-x   4 root root   4096 Jun  1  2021 aptdaemon
-rw-r--r--   1 root root  51576 Dec  1  2022 apt_inst.cpython-36m-x86_64-linux-gnu.so
-rw-r--r--   1 root root    227 Dec  1  2022 apt_inst.pyi
-rw-r--r--   1 root root 346784 Dec  1  2022 apt_pkg.cpython-36m-x86_64-linux-gnu.so
-rw-r--r--   1 root root   8900 Dec  1  2022 apt_pkg.pyi
drwxr-xr-x   3 root root   4096 Mar  3 22:23 aptsources
-rw-r--r--   1 root root    226 Dec  1  2022 python_apt-1.6.6.egg-info

To fix this issue:

To fix this issue just create a link named 'apt_pkg.so' points to "/usr/lib/python3/dist-packages/apt_pkg.cpython-36m-x86_64-linux-gnu.so"

$ cd /usr/lib/python3/dist-packages
$ sudo ln -s apt_pkg.cpython-36m-x86_64-linux-gnu.so  apt_pkg.so

Tmux startup script tempalte

 Tmux script template

#!/bin/bash

SESSION_NAME=dev

# new-session -c start-directory -n window-name -s session-name -t group-name -x width -y height [shell-command]
tmux has-session -t ${SESSION_NAME} 2>&1 >/dev/null

#if [ $? -ne 0 ];then
#	source /opt/.../export.sh
#	tmux new-session -s $SESSION_NAME -n main -d
#	tmux new-window  -c $SRC_DIR -n editor
#	tmux new-window  -c $BUILD_DIR -n build
#	tmux attach -t $SESSION_NAME
#	tmux select-windows -t $SESSION_NAME:0
#else
#	echo "Session is already started"
#fi
#

if [ $? -ne 0 ]; then
    # create new session
    tmux new-session -s ${SESSION_NAME} -n main -d
    tmux split-window -h
    tmux split-window -v
    tmux attach -t ${SESSION_NAME}
else
    echo "Tmux session is already created. Use 'tmux attach -t SESSION_NAME'"
fi

 Just a note.

Original post: CPU performance over time from T420 to T480