zlacker

Linux has a very flexible LED framework, and there's a variety of different "triggers" one can use to drive the LEDs. CPU usage, disk usage, network device usage, backlight level, usb port usage, audio are all different triggers one can control an LED via, that are baked into the kernel[1]. There's userland devices one can use to do whatever else one wants.

This isn't as aesthetic as say, the LiveWire[2] mention in the comments. But it's readily available on almost all systems, and is a very flexible ambient indicator.

There's a lot of really really fun good stuff in the comments here. Ambient is good, but to me, I want computing that exposes the causal relationships of what is happening as it's processing, as it's running. "This button was clicked so I'm trying to change the screen brightness now." All of the entities of computing, the data, these user events, should be reified, should be made into a logged sequence of what is happening. From that basis, we can all be free to explore computing, and to- EventSourcing style- extend the graph of computing as we might see fit.

[1] https://github.com/torvalds/linux/tree/master/drivers/leds/t...

[2] https://news.ycombinator.com/item?id=28348148