ITP Blog

Intro to Physical Computing - Week 3

September 19, 2018

Interactive Technology Observation

For my piece of public interaction technology, I picked the humble public bus pull-cord.

interaction device

The pull-cord is so intuitive that I can remember as a child wanting to pull on the cord to stop the bus. The affordance of the pull-cord is as direct as it’s name, pull the brightly colored, high contrast cord and something will happen. We’ve been taught through public transportation ettiqute to constrain ourselves from only pulling the cord when it’s one’s stop. And there’s the immediate feedback of a bell noise and light indicating “bus stopping” upon pulling the cord.

I’ve never seen anyone try to push the pull-cord or been confused about it’s purpose on the bus. The minimum instructions that pulling the cord signals for stop is an indication to its simplicity. Perhaps the only confusion stems from how high the cord is placed, riders know its there but can struggle to find it if not looking.

Building a Reaction Tester Using Arduino Digital Pins

For my lab project that uses an Arduino’s digital inputs and outputs, I built a reaction timer game. The first prototype and the Arduino’s program is inspired by this Instructables project. Shown below is a slightly modified circuit from the one described in the tutorial. Instead of using only one LED to indicate the beginning of the game and start of the reaction timer, I used two LEDs. The yellow LED flickers to indicate the beginning of the game and then the player has to press the button as soon as the green LED turns on (code).

tutorial based

I continued to iterate on this prototype by adding a piezo buzzer if the player’s reaction was too slow. The buzzer was connected to digitial pin 7 and then the Arduino program would generate a noise using tone if the player’s reaction time was greater than 1000ms (code).

buzzer prototype

Video) of the buzzer prototype.

Finally, I decided to modify the circuit so that it behaved more like a drag racing Christmas tree. The new game behavior became:

  • Player presses button to begin game
  • Yellow LED turns on to indicate an activate game
  • When yellow LED turns off, the buzzer sounds, and the player must react and press the button again
  • If the player’s reaction time is under 500ms, the green LED turns on indicating a fast time
  • If the player’s reaction time is over 500ms, the red LED turns on indicating a slow time

A red LED was added to the circuit as part of these changes and I refactored the code to follow this behavior.

final prototype

Video of the finished prototype.

Future Thoughts

Some thoughts I had if I were to redo this project or continue to build on it:

  • Build a proper case/interface for the game (actually attempting to laser cut a an acrylic case for my Intro to Fabrication project)
  • Use a bigger, proper push button instead of the prototype breadboard push buttons
  • Add more yellow LED lights that blink down to mimic a drag racing Christmas tree even more
  • Adjust the tone of the buzzer based on how slow the player is

Adrian Bautista

NYU ITP documentation blog.
Words are my own.