System Info Display

Display basic system information and energy meter readings (fetched via IOBroker) on a ST7735 OLED display (using luma.oled). This is a re-implementation of "System Info Display" by [Alvaro Valdebenito][avaldebe].

ST7735 on a Raspberry Pi

After sys_info.py is called, the display will be updated once a minute.

Hardware Setup

This script is built for a ST7735 OLED display. Please make sure your wiring is correct. The wiring below is for a 1.77" OLED offered by AZ Delivery.

TFT LCD pin	RaspberryPi pin	wire color
LEDA	3.3v (pin 1)	orange
CS (SS)	GOIO 8 / CE0 (pin 24)	cyan
RS (Reg. Sel.)	GPIO 23 (pin 16)	purple
RES (Reset)	GPIO 24 (pin 18)	blue
SDA (MOSI)	GPIO 10 / MOSI (pin 19)	green
SCK	GPIO 11 / SCLK (pin 23)	pink
VCC	5v (pin 4)	red
GND	GND (pin 25)	black

Installation for python3

luma.oled

sudo apt install python3-dev python3-pip libfreetype6-dev libjpeg-dev build-essential
sudo -H pip3 install --upgrade luma.oled

Additional dependencies on Raspbian Stretch Lite

sudo apt install libopenjp2-7 libtiff5
sudo -H pip3 install psutil

Customize Script

Energy Meter readings are fetched via IOBroker. Please make sure to setup an energy meter adapter in IOBroker and change the energy meter objects in sys_info.py line 54 and line 56 to the object names in your IOBroker instance.

Start after boot

There are different options to start a job after boot, see here. This are the ones I have tried/plan to try out.

• cronjob: easy to set-up, need to reboot to update the script
• service: harder to set-up, easy to start/stop

Run as a cronjob

Add the following lines to your crontab (crontab -e)

@reboot bash -lc $HOME/RpiHwMeterMonitor/sys_info.py &

The bash -l is needed to get the right $PATH for iwconfig, which in turn is needed for the wifi signal strength.

Run as a service

The systemd service file (RpiHwMeterMonitor.service) defines a new service called RpiHwMeterMonitor, which is to be launched once the multi-user environment is available.

# copy the service file
sudo cp RpiHwMeterMonitor.service /lib/systemd/system/

# set the required permissions
sudo chmod 644 /lib/systemd/system/RpiHwMeterMonitor.service

# enhable new service
sudo systemctl daemon-reload

# start/stop/reload service
sudo systemctl start RpiHwMeterMonitor
sudo systemctl stop RpiHwMeterMonitor
sudo systemctl reload-or-restart RpiHwMeterMonitor

# check service status
systemctl status RpiHwMeterMonitor

# start automatically after reboot
sudo systemctl enable RpiHwMeterMonitor # start after reboot
#sudo systemctl disable RpiHwMeterMonitor # don't start
sudo reboot

For more info about systemctl usage, see this tutorial, and this article about auto restart crashed services.