Ledbridge is our main software for controlling LED-Displays.

Ledbridge is our main software for controlling LED-Displays. It was initially developed in 2008 to replace the proprietary, windows-only software LedShowT9 and allow the LEDsMob to be controlled from Linux systems. Since then a lot of features have been added to it. It's modular design allows it to capture frames from all kinds of sources and drive various kinds of displays. Ledbridge is primary designed for Linux systems but, while lacking some Linux specific features, it has also been successfully tested on Mac OS X and FreeBSD. Windows is not supported at the moment. Like all of our software it is open source and can be obtained from our ledtools repository.

The screenshot on the right shows ledbridge capturing a 48x64 pixel part of the screen - in this case a part of a fractal generated by XaoS - and transferring it to a T9 display attached to eth0, the default interface. The content "below" the highlighted capture window is processed.

The input modules currently supported by ledbridge are:

  • AWT - Captures a part of the screen using Java (for OS X)
  • Aurinko - An Aurinko stream (see the Aurinko/Toublo page)
  • SHM - Shared memory, to connect to other ledbridge instances or other software such as ledtext or ledfb (see below)
  • V4L - Video 4 Linux, for capturing video from a webcam or TV-card (Linux only)
  • X11 - Captures a part of the screen using X11 (for Linux, doesn't work on Mac - faster the AWT)
  • TestPattern - Generate simple Testpattern to see if your LED-Display is OK.

It can optionally process the frames by applying a filter to them:

  • Crop - Cut out a part of the video
  • Dedistort - Apply perspective corrections to the video
  • Rotate - Rotate the image 90, 180, 270 degrees, flip it or turn it upside-down
  • Scale - Scales the image
  • Stencil - Cuts out a part of the image using a description file. Useful for matrices with unpopulated LED-locations like on the Maybach prototype project

... and send it to various displays:

  • Bobo: A bobogadetto attached to the USB-port
  • Linear: A linear 4-bit matrix, like the one we developed for Areus engineering
  • SHM: Shared memory
  • T9: For T9 LED matrices like the LEDsMOB. Replaces LedShowT9
  • VNCServer: Experimental, send frames to connected VNC clients
  • WS2811: Control a string of WS2811 or WS2812 LEDs using an Arduino as protocol translator (Arduino Sketch included)

The typical usage scenario is to capture frames from an X11 or AWT source and transfer it to a display. But we also provice add-on software for generating text or video frames without starting an X-Server. This allows ledbridge to run on embedded devices such as a Sheevaplug:

  • ledfb (Linux only): Emulates a framebuffer device in userspace to allow framebuffer and SDL-based software to run on LED-displays.
  • ledmplayer (Linux only): ledfb shellscript to hook it up to MPlayer, the movie player
  • ledtext: For text animations (running, flashing, colorchanging, ...). We used this for our live twitterwall.
Materials & Technilogy: C, c++, Java | 11 July, 2011 - 10:25 | Simon | Comments 0 |