Install CircuitPython
This guide assumes that you've gotten your Raspberry Pi up and running, and have CircuitPython installed. If not, check out the guide:
To install the library for the Pi OLED, enter the following into the terminal:
sudo pip3 install adafruit-circuitpython-ssd1306
If that complains about pip3 not being installed, then run this first to install it:
sudo apt-get install python3-pip
We also need PIL to allow using text with custom fonts. There are several system libraries that PIL relies on, so installing via a package manager is the easiest way to bring in everything:
sudo apt-get install python3-pil
Enable I2C
To enable i2c, you can follow our detailed guide on configuring the Pi with I2C support here.
You also need to install Blinka support as detailed here
After you've enabled I2C you will need to shutdown with sudo shutdown -h now
Once the Pi has halted, plug in the PiOLED. Now you can power the Pi back up, and log back in. Run the following command from a terminal prompt to scan/detect the I2C devices
sudo i2cdetect -y 1
You should see the following, indicating that address 0x3c (the OLED display) was found
Verify I2C Device
You can run our buttons example, which will let you press various buttons and see them mimicked on the OLED.
Create a new file with nano ~pi/bonnet_buttons.py and paste this code below in! Then save it.
# SPDX-FileCopyrightText: 2017 James DeVito for Adafruit Industries
# SPDX-License-Identifier: MIT
# This example is for use on (Linux) computers that are using CPython with
# Adafruit Blinka to support CircuitPython libraries. CircuitPython does
# not support PIL/pillow (python imaging library)!
import board
import busio
from digitalio import DigitalInOut, Direction, Pull
from PIL import Image, ImageDraw
import adafruit_ssd1306
# Create the I2C interface.
i2c = busio.I2C(board.SCL, board.SDA)
# Create the SSD1306 OLED class.
disp = adafruit_ssd1306.SSD1306_I2C(128, 64, i2c)
# Input pins:
button_A = DigitalInOut(board.D5)
button_A.direction = Direction.INPUT
button_A.pull = Pull.UP
button_B = DigitalInOut(board.D6)
button_B.direction = Direction.INPUT
button_B.pull = Pull.UP
button_L = DigitalInOut(board.D27)
button_L.direction = Direction.INPUT
button_L.pull = Pull.UP
button_R = DigitalInOut(board.D23)
button_R.direction = Direction.INPUT
button_R.pull = Pull.UP
button_U = DigitalInOut(board.D17)
button_U.direction = Direction.INPUT
button_U.pull = Pull.UP
button_D = DigitalInOut(board.D22)
button_D.direction = Direction.INPUT
button_D.pull = Pull.UP
button_C = DigitalInOut(board.D4)
button_C.direction = Direction.INPUT
button_C.pull = Pull.UP
# Clear display.
disp.fill(0)
disp.show()
# 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)
while True:
if button_U.value: # button is released
draw.polygon([(20, 20), (30, 2), (40, 20)], outline=255, fill=0) # Up
else: # button is pressed:
draw.polygon([(20, 20), (30, 2), (40, 20)], outline=255, fill=1) # Up filled
if button_L.value: # button is released
draw.polygon([(0, 30), (18, 21), (18, 41)], outline=255, fill=0) # left
else: # button is pressed:
draw.polygon([(0, 30), (18, 21), (18, 41)], outline=255, fill=1) # left filled
if button_R.value: # button is released
draw.polygon([(60, 30), (42, 21), (42, 41)], outline=255, fill=0) # right
else: # button is pressed:
draw.polygon(
[(60, 30), (42, 21), (42, 41)], outline=255, fill=1
) # right filled
if button_D.value: # button is released
draw.polygon([(30, 60), (40, 42), (20, 42)], outline=255, fill=0) # down
else: # button is pressed:
draw.polygon([(30, 60), (40, 42), (20, 42)], outline=255, fill=1) # down filled
if button_C.value: # button is released
draw.rectangle((20, 22, 40, 40), outline=255, fill=0) # center
else: # button is pressed:
draw.rectangle((20, 22, 40, 40), outline=255, fill=1) # center filled
if button_A.value: # button is released
draw.ellipse((70, 40, 90, 60), outline=255, fill=0) # A button
else: # button is pressed:
draw.ellipse((70, 40, 90, 60), outline=255, fill=1) # A button filled
if button_B.value: # button is released
draw.ellipse((100, 20, 120, 40), outline=255, fill=0) # B button
else: # button is pressed:
draw.ellipse((100, 20, 120, 40), outline=255, fill=1) # B button filled
if not button_A.value and not button_B.value and not button_C.value:
catImage = Image.open("happycat_oled_64.ppm").convert("1")
disp.image(catImage)
else:
# Display image.
disp.image(image)
disp.show()
Run sudo python3 bonnet_buttons.py to run the demo, you should see something like the below:
Press buttons to interact with the demo. Press the joystick + buttons at once for an Easter egg!
Running Scripts on Boot
You can pretty easily make it so this program (or whatever program you end up writing) run every time you boot your Pi.
The fastest/easiest way is to put it in /etc/rc.local
Run sudo nano /etc/rc.local and add the line
sudo python /home/pi/bonnet_buttons.py &
on its own line right before exit 0
Then save and exit. Reboot to verify that the screen comes up on boot!
Library Usage
In the examples subdirectory of the Adafruit_CircuitPython_SSD1306 repository, you'll find more examples which demonstrate the usage of the library.
To help you get started, I'll walk through the bonnet_buttons.py code below, that way you can use this file as the basis of a future project.
Python Library Setup
import board import busio from digitalio import DigitalInOut, Direction, Pull from PIL import Image, ImageDraw import adafruit_ssd1306
First, a few modules are imported, including the adafruit_ssd1306 module which contains the OLED driver classes. The code also imports board (containing the Raspbery Pi pin definitions), busio (communication with the i2c and spi buses), and digitalio (to control the Raspberry Pi's pins).
You can also see some of the Python Imaging Library modules like Image, ImageDraw, and ImageFont being imported. Those are, as you can imagine, are for drawing images, shapes and text/fonts!
Display Setup
# Create the I2C interface. i2c = busio.I2C(board.SCL, board.SDA) # Create the SSD1306 OLED class. disp = adafruit_ssd1306.SSD1306_I2C(128, 64, i2c)
The next bit of code creates the I2C interface (which the display on the bonnet communicates over) and creates a SSD1306 OLED class. Note that we are passing SSD1306_I2C 128 and 64, those values correspond to the bonnet's OLED display.
# Input pins: button_A = DigitalInOut(board.D5) button_A.direction = Direction.INPUT button_A.pull = Pull.UP button_B = DigitalInOut(board.D6) button_B.direction = Direction.INPUT button_B.pull = Pull.UP button_L = DigitalInOut(board.D27) button_L.direction = Direction.INPUT button_L.pull = Pull.UP button_R = DigitalInOut(board.D23) button_R.direction = Direction.INPUT button_R.pull = Pull.UP button_U = DigitalInOut(board.D17) button_U.direction = Direction.INPUT button_U.pull = Pull.UP button_D = DigitalInOut(board.D22) button_D.direction = Direction.INPUT button_D.pull = Pull.UP button_C = DigitalInOut(board.D4) button_C.direction = Direction.INPUT button_C.pull = Pull.UP
Next up we define the pins that are used for the joystick and buttons. The Joystick has Left, Right, Center (press in), Up and Down. There's also the A and B buttons on the right. Each one should be set as an input with pull-up resistor (Pull.UP in the code)
Display Initialization
# Clear display.
disp.fill(0)
disp.show()
# 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)
The next chunk of code clears the display by inverting its fill with fill(0) and then writing to the display with show().
Then it will configure a PIL drawing class to prepare for drawing graphics. Notice that the image buffer is created in 1-bit mode with the '1' parameter, this is important because the display only supports black and white colors.
We then re-draw a large black rectangle to clear the screen. In theory we don't have to clear the screen again, but its a good example of how to draw a shape!
Button Input and Drawing
while True:
if button_U.value: # button is released
draw.polygon([(20, 20), (30, 2), (40, 20)], outline=255, fill=0) #Up
else: # button is pressed:
draw.polygon([(20, 20), (30, 2), (40, 20)], outline=255, fill=1) #Up filled
if button_L.value: # button is released
draw.polygon([(0, 30), (18, 21), (18, 41)], outline=255, fill=0) #left
else: # button is pressed:
draw.polygon([(0, 30), (18, 21), (18, 41)], outline=255, fill=1) #left filled
if button_R.value: # button is released
draw.polygon([(60, 30), (42, 21), (42, 41)], outline=255, fill=0) #right
else: # button is pressed:
draw.polygon([(60, 30), (42, 21), (42, 41)], outline=255, fill=1) #right filled
if button_D.value: # button is released
draw.polygon([(30, 60), (40, 42), (20, 42)], outline=255, fill=0) #down
else: # button is pressed:
draw.polygon([(30, 60), (40, 42), (20, 42)], outline=255, fill=1) #down filled
if button_C.value: # button is released
draw.rectangle((20, 22, 40, 40), outline=255, fill=0) #center
else: # button is pressed:
draw.rectangle((20, 22, 40, 40), outline=255, fill=1) #center filled
if button_A.value: # button is released
draw.ellipse((70, 40, 90, 60), outline=255, fill=0) #A button
else: # button is pressed:
draw.ellipse((70, 40, 90, 60), outline=255, fill=1) #A button filled
if button_B.value: # button is released
draw.ellipse((100, 20, 120, 40), outline=255, fill=0) #B button
else: # button is pressed:
draw.ellipse((100, 20, 120, 40), outline=255, fill=1) #B button filled
if not button_A.value and not button_B.value and not button_C.value:
catImage = Image.open('happycat_oled_64.ppm').convert('1')
disp.image(catImage)
else:
# Display image.
disp.image(image)
disp.show()
Once the display is initialized and a drawing object is prepared, you can draw shapes, text and graphics using PIL's drawing commands.
This is a basic polling example - we'll check each button.value in order, and draw a different shape - a directional arrow or a round circle) depending on whether the button is pressed. If the button is pressed we have the shape filled in. If the button is not pressed, we draw an outline only
Then we run disp.image(image) and disp.show() to actually push the updated image to the OLED. This is required to actually make the changes appear!
Speeding up the Display
For the best performance, especially if you are doing fast animations, you'll want to tweak the I2C core to run at 1MHz. By default it may be 100KHz or 400KHz
To do this edit the config with sudo nano /boot/config.txt
and add to the end of the file
dtparam=i2c_baudrate=1000000
reboot to 'set' the change.
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