|Skills||electronics, microcontrollers, linux, mqtt, webservices, python, twisted, ansible|
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.
- 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)
- (Done-ish) Spacealert with message. Still missing working shardik code.
- IRC integration via shardik: .display [message]
- (Done) MPD songs: What are we listening to?
- Wifi SSIDs being broadcast / MAC count stats
- (Done) Next and tram / metro / nightbuses
- (Done) Incoming rain alerts (https://www.buienradar.nl/overbuienradar/gratis-weerdata, https://br-gpsgadget-new.azurewebsites.net/data/raintext/?lat=52.35&lon=4.83)
- (Done) Clock
- (Done) Midnights ("Midnight in «City»")
- Days until Brexit
- Drama stats
- Parse the ML archives, get stats from there --- https://techinc.nl/cgi-bin/mailman/listinfo/ + https://techinc.nl/cgi-bin/mailman/listinfo/discuss
- Keep track of IRC stats --- https://gist.github.com/habnabit/5823693
- API/Interface for countdowns.
- (Done) Next TI events
- Space events
- Next interesting rocket launch (SpaceX, Soyuz, etc...)
- ISS flyovers
- (Done) Zonsopkomst en -ondergang tijden
- (Done) Maan standen. volle maan, nieuwe, etc.
- External content
- (Done) Btc/Eth values --- https://www.cryptocompare.com/
- https://radar.squat.net --- https://0xacab.org/radar/drupal-make/wikis/api/1.1/notes
- Radio Yerevan Jokes: https://duckduckgo.com/Radio_Yerevan_jokes?iax=1&ia=about
- Random Jargon file entries
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
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.
- 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.