Use nice I2C OLED display

March 23, 2018 · View on GitHub

Install the packages you need

sudo apt-get update && sudo apt-get upgrade
sudo apt-get install i2c-tools

Increase the I2C baudrate from the default of 100KHz to 400KHz

sudo nano /boot/config.txt

add this line at the end of the file

dtparam=i2c_arm=on,i2c_baudrate=400000

Add your user to I2C group

sudo usermod -a -G i2c loragw

then logout (CTRL-d) and log back so that the group membership permissions take effect

sudo reboot

Check you can see I2C OLED

 i2cdetect -y 1

you should see something in your OLED I2C address, here it's 3C (Hex)

     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: -- -- -- -- -- -- -- --

Install OLED Python library

Install dependencies

sudo apt install python-dev python-pip libfreetype6-dev libjpeg-dev build-essential

Install luma OLED core

You can go for a coffe after this one, takes some time

sudo -H pip install --upgrade luma.oled

Get examples files (and font)

sudo mkdir -p /usr/share/fonts/truetype/luma
git clone https://github.com/rm-hull/luma.examples.git
sudo cp luma.examples/examples/fonts/*.ttf /usr/share/fonts/truetype/luma/

But if you want to run all examples, which I do not recommand because it takes SD space and very long time to install, type the following

sudo apt install libsdl-dev libportmidi-dev libsdl-ttf2.0-dev libsdl-mixer1.2-dev libsdl-image1.2-dev
sudo pip install --upgrade setuptools
cd luma.examples
sudo -H pip install -e .

Configure OLED

Configure OLED Hardware

You may need to change the following line in oled.py according to the connected OLED type and it I2C address.

The i2c adress can be seen with i2cdetect -y 1

     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: -- -- -- -- -- -- -- --

If you already installed all the Gateway software it's located in /opt/loragw/oled.py else in ~/LoraGW-Setup/oled.py

Mine is 1.3" SH1106 with 0x3c address so my config is

serial = i2c(port=1, address=0x3c)
device = sh1106(serial)

But as an example, for SSD1306 oled with address 0x3d

serial = i2c(port=1, address=0x3d)
device = ssd1306(serial)

Then you can check OLED display with, shold display something

./oled.py

Configure OLED software

You may need to change the following line in /opt/loragw/oled.py according to the connected network interface you have

Mine is wlan0 for WiFi and uap0 for WiFi access point

draw.text((col1, line1),"Host :%s" % socket.gethostname(), font=font10, fill=255)
draw.text((col1, line2), lan_ip("wlan0"),  font=font10, fill=255)
draw.text((col1, line3), network("wlan0"),  font=font10, fill=255)
draw.text((col1, line4), lan_ip("uap0"),  font=font10, fill=255)
draw.text((col1, line5), network("uap0"),  font=font10, fill=255)

if for example it's running from RPI 3 with eth0 code could be

draw.text((col1, line1),"Host :%s" % socket.gethostname(), font=font10, fill=255)
draw.text((col1, line2), lan_ip("eth0"),  font=font10, fill=255)
draw.text((col1, line3), network("eth0"),  font=font10, fill=255)
draw.text((col1, line4), lan_ip("wlan0"),  font=font10, fill=255)
draw.text((col1, line5), network("wlan0"),  font=font10, fill=255)

Once all is setup and running you can enable disbale OLED service with

sudo systemctl enable oled
sudo systemctl disable oled

And start or stop the OLED service with

sudo systemctl start oled
sudo systemctl stop oled