Ledslie

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Projects
23c6c9d3ff88b3f8-cut.jpg
Participants Chotee
Skills electronics, microcontrollers, linux, mqtt, webservices, python, twisted, ansible
Status Active
Niche Electronics
Purpose Infrastructure

Interface to display information

  • It is a Grayscale display of 144x24 pixels that displays information.
  • It lives at http://ledslie.ti/ and is accessible at the space via a website and MQTT.

Interfaces

  • At http://ledslie.ti/ you to submit content, such as animated GIFs, from your browser.
  • You can publish content by posting content to the web-service.
  • You can publish content directly to the mqtt broker that lives on ledslie.ti:1883.

Known issues (and their solution)

  • Symptoms: The screens network dependent screens are missing, time might be incorrect. http://ledslie.ti is not available.
  • Problem: The DHCP server was not available when Ledslie started up, and is now in network-less mode. Likely there was a space power failure.
  • Solution: Once the network is stable again, cycle the power of Ledslie, it should restart properly.

Content ideas (in no specific order)

How it works

Wifi --RF> Getchip --USB2> Teensy --[data,clock,latch]> Led-pannel

The led-panel takes 20V DC as input. At full output it's pulling about 4A, or about 80W. There's a small switcher-board that supplies the 5v the the getchip and Teensy from those 20V.

The Teensy drive code is here: https://github.com/techinc/ledmatrix/tree/master/ledmatrix144x24

The Ledslie code can be found here: https://github.com/techinc/ledslie

Software

The system's software is available at https://github.com/techinc/ledslie , this repo contains code that's running on the Display.

Possible Hardware expansions

  • Add another panel by adding a USB2 hub, and modding another of the led panels with the teensy taking over the driving logic.

FAQ

  • Q: What's that noise? A: The panel is being driven at rates way beyond the original design and we're well in the audible frequencies with the refresh-rates and some components are merrily humming along.
  • Q: Why are some points brighter then others? A: Turns out that LEDs do wear. In their previous life some LEDs were on for years, while others were always off. There's plans to compensate for this in software.