Blinking the LED using only the GPU (which weirdly is responsible for the initial stages of booting the rpi):

https://github.com/hermanhermitage/videocoreiv/tree/master/b...

The BCM2835 is probably best described as a VideoCore IV GPU with an ARM core bolted on the side. :)

Last year I wrote a script to output in morse the ip address of a headless raspberry pi on startup. I have never needed it but it's cool. https://gist.github.com/rnhmjoj/11143783

that led blinking example makes me sad :(

Why?

I mean, Blinky is the "Hello World" of embedded software. When was the last time a hello world aroused you? The point of this is not the blinky, it's the "omg erlang vm on raspberry pi".

Now let's level up and see an ISR using the Erlang VM.

perhaps the way to make it wow, is to connect 100,000 led to it, and each controlled by a separate browser socket. V8/node folks will cry a little.

Connecting 100k LEDs to a RPi is an interesting engineering challenge in its own right. (Also, if one LED consumes 10 mA / 30 mW, 100k will consume 1000 A / 3 kW.)

A more realistic thing would be a telnet chat server: code is dead simple, and the ability to handle NH / slashdot / reddit crowd on a RPi would indeed be impressive.

Not exactly, there are many LED driver ICs with SPI, and you don't really need a 1000A-capable 3V bus, just 500 or so small wall-warts ;)

Not lazy enough. Just talk Art-Net, the instruments are now Someone Else's Problem.

More lazy: attach yourself to one of these LED-based megascreens in sport stadiums. Output ordinary composite video and you're done!

LED Display seems to be a valid short-cut to your problem.

Me too. Should have used a full V8/Node.js stack to do it. =)

And used LFE (lisp flavoured erlang) in place of Elixir, since Elixir is Rubyesque, a fav of the web dev crowd, vs. the parenthetical LFE!

All joking aside, I like seeing BEAM everywhere, and Elixir is a great language.

I can't wait until folks start mixing Erlang, Elixir, and LFE in production codebases (which I reckon should, technically, be possible given some better build tools).

I'm not sure what's in production, but Duncan has talked about just this in his talk "The State of LFE: A Lisp Flavoured Smörgåsbord" 8 months ago:

  https://vimeo.com/102108797