My concern was when I SSH into the pi as root, do I just run the commands? I'm pretty novice at linux to be honest. This dude seems to have everything scripted out on his actual site. I just wasn't sure if following the copy/paste commands would work on our setup since it's not the standard Pi image.
Programming The OLED Display
To get the display working, we need to run a Python script. You’ll need to boot your Pi up to do this.
The Raspberry Pi communicates with the display using I2C communication, so you’ll also need to make sure that this is enabled in your preferences or do it through the command line by running:
sudo raspi-config
Then select Interfacing Options, then I2C, then select Yes and then reboot the Pi with the following command:
sudo reboot
You’ll also need to ensure that the python-smbus and i2c-tools libraries are both installed. They should be by default, but it’s worth checking, by running the following commands:
sudo apt-get install python-smbus
sudo apt-get install i2c-tools
sudo pip3 install Adafruit_BBIO
While you’re at this stage, it’s also worth checking that your Pi is able to see your display. You can display a list of devices connected to the I2C bus by entering the following command:
sudo i2cdetect -y 1
This should display an output similar to the below:
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- 3c -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
This indicates that a device has been detected and it’s address is 0x3c. If you don’t get anything showing up here then check your connections to your display and make sure that you’ve got I2C communication enabled on your Pi.
Don’t proceed with trying to program the display if you aren’t getting an address in this step. This means that the Pi isn’t able to see the display, and it won’t be able to display anything until it is.
Next, let’s have a look at the script and how to install it. This script is mostly based on one of the example scripts in the Adafruit Python Library for OLED display modules, with a few changes by Shakhizat Nurgaliyev to add the CPU temperature and change the format of the display.
# Copyright (c) 2017 Adafruit Industries
# Author: Tony DiCola & James DeVito
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
import time
import Adafruit_GPIO.SPI as SPI
import Adafruit_SSD1306
from PIL import Image
from PIL import ImageDraw
from PIL import ImageFont
import subprocess
# Raspberry Pi pin configuration:
RST = None # on the PiOLED this pin isnt used
# Note the following are only used with SPI:
DC = 23
SPI_PORT = 0
SPI_DEVICE = 0
# Beaglebone Black pin configuration:
# RST = 'P9_12'
# Note the following are only used with SPI:
# DC = 'P9_15'
# SPI_PORT = 1
# SPI_DEVICE = 0
# 128x32 display with hardware I2C:
disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST)
# 128x64 display with hardware I2C:
# disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST)
# Note you can change the I2C address by passing an i2c_address parameter like:
# disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST, i2c_address=0x3C)
# Alternatively you can specify an explicit I2C bus number, for example
# with the 128x32 display you would use:
# disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST, i2c_bus=2)
# 128x32 display with hardware SPI:
# disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST, dc=DC, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE, max_speed_hz=8000000))
# 128x64 display with hardware SPI:
# disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST, dc=DC, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE, max_speed_hz=8000000))
# Alternatively you can specify a software SPI implementation by providing
# digital GPIO pin numbers for all the required display pins. For example
# on a Raspberry Pi with the 128x32 display you might use:
# disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST, dc=DC, sclk=18, din=25, cs=22)
# Initialize library.
disp.begin()
# Clear display.
disp.clear()
disp.display()
# Create blank image for drawing.
# Make sure to create image with mode '1' for 1-bit color.
width = disp.width
height = disp.height
image = Image.new('1', (width, height))
# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)
# Draw a black filled box to clear the image.
draw.rectangle((0,0,width,height), outline=0, fill=0)
# Draw some shapes.
# First define some constants to allow easy resizing of shapes.
padding = -2
top = padding
bottom = height-padding
# Move left to right keeping track of the current x position for drawing shapes.
x = 0
# Load default font.
font = ImageFont.load_default()
# Alternatively load a TTF font. Make sure the .ttf font file is in the same directory as the python script!
# Some other nice fonts to try: http://www.dafont.com/bitmap.php
# font = ImageFont.truetype('Minecraftia.ttf', 8)
while True:
# Draw a black filled box to clear the image.
draw.rectangle((0,0,width,height), outline=0, fill=0)
# Shell scripts for system monitoring from here : https://unix.stackexchange.com/questions/119126/command-to-display-memory-usage-disk-usage-and-cpu-load
cmd = "hostname -I |cut -f 2 -d ' '"
IP = subprocess.check_output(cmd, shell = True )
cmd = "top -bn1 | grep load | awk '{printf \"CPU Load: %.2f\", $(NF-2)}'"
CPU = subprocess.check_output(cmd, shell = True )
cmd = "free -m | awk 'NR==2{printf \"Mem: %s/%sMB %.2f%%\", $3,$2,$3*100/$2 }'"
MemUsage = subprocess.check_output(cmd, shell = True )
cmd = "df -h | awk '$NF==\"/\"{printf \"Disk: %d/%dGB %s\", $3,$2,$5}'"
Disk = subprocess.check_output(cmd, shell = True )
cmd = "vcgencmd measure_temp |cut -f 2 -d '='"
temp = subprocess.check_output(cmd, shell = True )
# Write two lines of text.
draw.text((x, top), "IP: " + str(IP,'utf-8'), font=font, fill=255)
draw.text((x, top+8), str(CPU,'utf-8') + " " + str(temp,'utf-8') , font=font, fill=255)
draw.text((x, top+16), str(MemUsage,'utf-8'), font=font, fill=255)
draw.text((x, top+25), str(Disk,'utf-8'), font=font, fill=255)
# Display image.
disp.image(image)
disp.display()
time.sleep(.1)
OLED Display Python ScriptDownload
You’ll need to download the original Adafruit example library from Github to get the setup complete by using these commands in your terminal:
sudo python -m pip install --upgrade pip setuptools wheel
git clone https://github.com/adafruit/Adafruit_Python_SSD1306.git
Open a new terminal window, then navigate to the library’s directory:
cd Adafruit_Python_SSD1306
Install the library for Python 3:
sudo python3 setup.py install
You can then run the above stats.py file or the example stats.py file in the Adafruit directory, you’ll just get a slightly different display layout with the Adafruit example.
Change to the directory containing the stats.py script:
cd examples
Execute the script:
python3 stats.py
You can test run the script to check that your display is working correctly and you don’t get any errors before setting it to run automatically.
To set the script to run automatically, you’ll need to find the script’s directory, then open crontab and add a line to run the script:
@reboot python3 /home/pi/stats.py &
You’ll obviously need to change the directory /home/pi/ to reflect the directory where you have your script saved.
Don’t forget to add the & at the end, this tells the Pi to continue starting up and run the script in the background.
Raspberry Pi 4 Desktop Case Display Showing stats
Reboot the Pi to automatically run the script and you should then see the stats shown on the OLED display when it starts up.
