zerodisplay

The goal of this tiny project is to display outside temperature and a few other metrics (CO2, atmospheric pressure) on a display attached to a fridge. This assume this data is already collected elsewhere and available via HTTP. Specifically this assumes https://github.com/vladak/weather.

Hardware

• Raspberry Pi Zero WH
• Adafruit 2.13" Monochrome E-Ink Bonnet
• Apple Magic mouse.. wait for it.. transparent enclosure
• a nice drawing

It looks like this:

The buttons are currently unused, might drill the holes for them one day, in order to be able to switch to e.g. a name-of-the-day display. Similarly, if the Pi tends to overheat, will have to drill some holes to the top of the enclosure.

Install

per https://learn.adafruit.com/2-13-in-e-ink-bonnet/usage

• enable SPI (in the Interfaces menu):

sudo raspi-config

• check there are some /dev/spidev0.* devices
• install pre-requisites

  sudo apt-get install -y python3-venv
  sudo apt-get install -y fonts-dejavu
  sudo apt-get install -y libopenjp2-7 # needed for Pillow
  sudo apt-get install -y libatlas-base-dev # needed for numpy used by prometheus-api-client

• checkout the Git repository

  [[ ! -d srv ]] || mkdir /srv
  sudo chown pi /srv
  sudo apt-get install -y git
  git clone https://github.com/vladak/zerodisplay /srv/zerodisplay

• install requirements:

  cd /srv/zerodisplay
  python3 -m venv env
  . ./env/bin/activate
  export CFLAGS=-fcommon # needed for RPi.GPIO per https://askubuntu.com/a/1330210
  pip install -r requirements.txt

• configure the service: create /srv/zerodisplay/environment file and setup these environment variables inside:
  • ARGS: arguments to the report program
  • the file can look like this (no double quotes):

ARGS=-U http://localhost:8111 -l debug --temp_sensor_name foo/bar

• enable+start the service

  sudo cp /srv/zerodisplay/zerodisplay.service /etc/systemd/system/
  sudo systemctl enable zerodisplay
  sudo systemctl daemon-reload
  sudo systemctl start zerodisplay
  sudo systemctl status zerodisplay