Source Repository for "Grüne Signale" (Fork von netzbegruenung/green-signals)
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Stefan Schmidt-Bilkenroth d8535347ce adding GPLv3 license 7 months ago
.gitignore fix typo in gitignore 11 months ago
LICENSE.txt adding GPLv3 license 7 months ago update README 11 months ago add brief script to create ZIP from scripts 11 months ago fix evaluation for shutdown time 11 months ago tkinter.messagebox needs separate import 10 months ago



green-signals is the source code for "Grüne Signale" digital signage solution.


"Grüne Signale" offers a digital signage platform intended for use in showrooms. Main goal is to run a slideshow presenting end-user customizable contents with low efforts and budget required to set it up.

  • Low Budget solution
  • Low Knowledge requirements
  • All based on OpenSource modules and OpenSource itself
  • Playback of Images and Videos (muted)
  • Media files can be delivered in nested folders
  • Playback of Media follows alpabetical order
  • Easy to configure
  • Easy content updates via media download (zipped)
  • Once set up it shall run unattended
  • Written in Python 3


  • Raspberry Pi computer with Power supply, HDMI cable and SD-Card
  • Display with HDMI input (best with HDMI CEC support)
  • this can be a dedicated computer monitor or a TV Set
  • the Display should support FullHD Resolution (native 1920x1080)
  • LAN or WLAN connection
  • Mouse and Keyboard only needed for initial setup
  • VLC Application (included in Full Raspian Image)
  • Python-VLC module (needs to be installed during setup)
  • Python-crontab module (needs to be installed
  • Cloud account for automated media update (we suggest to use "Grüne Wolke")
  • The media files need to be provided as ZIP-File containing the images and videos

Media formats

  • Images in JPG or PNG format, same display duration for all images as configured
  • Videos in MOV, M4V or MP4 format
  • All media shall have 16:9 landscape format
  • media with a different aspect ratio will show black borders
  • All media will be scaled to fill the screen
  • Best resolution is 1920x1080 pixels (FullHD)
  • images larger than 1920x1080 are scaled down after download, which is quite slow on the Raspberry Pi
  • Video clips are muted during playback
  • Video clips should start and end with blending from/to a black frame (playback could flicker)

Environmental Topics

  • A Raspberry Pi computer has low energy consumption (usually less than 10W)
  • It can be configured for a safe shut down at night time (reduce light pollution)
  • A diplay supporting HDMI CEC will automatically switch to StandBy
  • Power for Raspberry Pi and display shall be turned off by a timer device
  • set the timer a few minutes after scheduled shut down of the Raspberry Pi computer
  • when the power is switched back on in the morning, The slideshow will autoomatically start and in background update the media files

Development Environment

  • The project is developed on a Raspberry Pi 400, any Raspberry Pi model (except Pico) is fine
  • Raspberry Pi 1 and Zero models may partially work (limitatons with video playback)
  • The project is intended to run on "Raspberry Pi OS" (based on Debian Buster)
  • support for other platforms is possible, but not tested


  • create setup script (
  • run pip3 install python-vlc
  • run pip3 install python-crontab
  • add green-signals to auto-start
  • write configuration file
  • user friendly GUI
  • configuration script (included in
  • add cronjob for safe shutdown at given time (obsolete, handled internally)
  • validation that remote URL points to a ZIP file.
  • improve on-barding
  • so far only dummy images for intial slideshow
  • provide manual in media slides and as documentation (Wiki?)
  • tutorials and other on-boarding guides (maybe with "Grünstreifen")
  • testing, testing
  • and more testing in real world ;-)


Chatbegruenung, Channel netzbegruenung-digitalsignage Stefan Schmidt-Bilkenroth,