Tuesday, March 15, 2011

Hey! You! Pay attention!

Most people have heard the term "dead man's switch" and know that it has to do with train locomotives, and maybe even know that there might be a pedal or a handle that the engineer had to push or manipulate or else the train will automatically stop. Anecdotally, if it's a pedal to be depressed, a brick would do, and you could go about your business :)

For my HCI class I show a brief clip from a History Channel documentary about locomotives. I recently found it on YouTube. You can see a modern "alerter" (instead of a dead man's pedal) and the engineer's explanation from 6:50 to 7:35 in the video.

The March/April 2011 Technology Review showed a "drowsiness detector" that works on the same principle but for automobiles.

Saturday, March 05, 2011


When I was in junior and senior high school I played around with a lot of electronics stuff, and I really like the look of glowing vacuum tubes (ah, McIntosh amps), so as an adult when I could afford it I bought a nixie clock :)

There was an article in Spectrum a while ago about how digital audio "doesn't sound right". The comments ripped the article and were the most interesting part. One of the links was to this video about "audio myths". Between 1:06 and 5:17 one of the speakers describes a cute single-blind experiment where he got an old tube amp and a SWTPC solid state amp and a switch and ... I won't spoil it for you :) Nice experiment, I think I'll show my students about perception.

The rest of the video is a presentation by Winer and more than you ever wanted to know about mixing, recording, dithering, jitter, distortion, ... and some good quotes like "16 bits through a sound card beats the best analog tape" (I think I got that right). The audio support files are here.

Three HCI things, and other stuff

Three recent HCI-UX related things:
  • Anthropologist Hank Delcore (Fresno State) and Kirsten Medhurst (Pelco) are interviewed about a great academic-industry synergy to improve user experiences of security products.
  • NPR featured a story on automation in the cockpit, and what can go wrong. "Automation surprise" indeed. You can also watch the recent PBS Nova on the crash of Air France 447 because they lost all airspeed indicators.
  • The March/April issue of Technology Review has an illustration showing "The need for speed: Even slight slowdowns online frustrate people and cost companies money". In 2000, according to Akamai, user would wait 8 seconds for a web page to load before navigating away. In 2009 it was down to 3 seconds. The entire article is "The Slow-Motion Internet", but I think you have to be a subscriber to read it online.
  • OK, one more thing. One of my favorite 90 second Don Norman videos that I've been showing students since 1994 has finally been uploaded to YouTube. It's a cute example of the difference between the users conceptual model and the underlying implementation model.

And now for the other stuff I promised:

One of the stranger DIY projects: hacking a manual typewriter for use as a computer keyboard.

Is the lifetime cost of LED light bulbs worth it? And, legendary Bell Labs engineer Robert W. Lucky gets phished and pays the price.

Really interesting Wired article about sports statistics: how consistent home field advantage is, and how umpires expand and contract the strike zone based on game conditions (scroll down to see the illustrations).