Small sampling of topics on brain during last 24 hours
Ice cream. it’s delicious. Also dim sum. Taste of Chicago is expensive; however, it has music.
Running in the rain is tremendous fun. Somewhat less fun when you arrive in Evanston after a microburst and discover that the same rain (and driving wind, and hail) that you’d been romping around in gleefully has also demolished an art festival, strewing tent poles, pottery, and large metal cacti across the stret, injuring several people. Nikki, Andrew, and I ended up waiting out the rain at the bookshop instead of roaming around town like we’d planned.
SJ started a publish or perish pledge wherein he is posting “almost all of my writing to public wikis ormailing lists, and to limit private or small-group emails to three lines (and a wiki link) apiece, for the next week.” I wonder how it’s going.
Ambitious idea of spiffiness: interwiki search engine.I’m a little worried about the curation process (its name is “Chris”) being scalable - also, just because it’s on a wiki doesn’t mean it’s good - just editable. But perhaps that’s the point. Creating a search engine only for the world-writable web.
Moodle has an education philosophy. I was pleasantly surprised - and want to emulate this for my projects (when relevant).
Piezoelectric materials. How do they work? We think of them as “the stuff in tiny tinny-sounding speakers.” Maybe we have the gist that “if you run electricity across it, it vibrates - if you vibrate the surface or otherwise bend it, it produces a voltage proportional to how much you’re bending it” (translation: you can pipe a signal into it and have it play that sound, or yell sound at it and have it pipe out the corresponding voltage signal). But why?
Apparently, these crystals have charges (stuck in dipoles) evenly distributed throughout the interior of their structure. When you bend the crystal, the even distribution isn’t quite so even any more, and a voltage results. To visualize this, think of a large rectangular dance hall with pairs of swing dancers (dipoles) - follows and leads - evenly spaced throughout the hall in a grid, every follow facing in the same direction, every lead facing in the same direction. It’s all balanced. Life is good.
Now take that dance hall and smoosh the floor into a different shape - maybe a large crew of breakdancers pours in from one side, forcing all the swingers to crowd away from the middle. Distribution of follows and leads not quite so even. In fact, the evenness of the distribution of swing dancers is directly influenced by how much space the breakdancers are taking up on the floor.
When you’re talking about electricity, an uneven charge distribution creates a potential difference - in other words, a voltage - across the thing in question. Piezos also work the other way, meaning that if the swing-dancers smoosh themselves into one side of the dance hall (a voltage is applied across the crystal), the breakdancers will flood in to fill the empty floorspace (the crystal will bend).
End effect: you have a speaker and/or microphone. Et voila.
Trickle is a simple yet nifty “get messages/updates out to a distributed wireless mote network” schema that uses a “polite gossip” policy. I may yammer about this later at some point if Andrew and I tinker up a simple implementation of it.
Life continues to be a constant uphill struggle against paralysis by planning. And apparently I am an overgrown puppy.*
*although I suspect this is in part a coping reaction to turn my overly-distracted-by-shininess tendencies into something cute and positive rather than an annoying negative - or at least it tends to work that way for most people. Not all, though.