Analog Input: Misguiding Knob

When I started thinking about building something that got information from an analog sensor to make a LED behave in an unexpected way, I was still thinking about Tom Igoe’s piece on making interactive art. Igoe asks us not to interpret our work for our audience, to stop trying to make statements. Instead, he asks us to foster conversation by suggesting interactions:

“Arrange the space, put in the items through they can take action, suggest a sequence of events through juxtaposition. If you want them to handle something, give it a handle. If they’re not supposed to touch something, don’t make it approachable. If they’re supposed to discover something hidden, give hints.”

This reminded me of Norman’s affordances and signifiers. With this in mind, I decided to build something that capitalized on users’ expectations about analog input and output (that as you turn a knob to the right, output will increase) to suggest a particular interaction, and would then subvert that interaction.

My product is a box with a line of 6 blue LED lights. Lights are sorted into pairs, and each pair is associated with a particular section of a knob’s trajectory. The leftmost pair is associated with the the initial third of the knob’s trajectory, the middle pair is associated with the middle third of the knob’s trajectory, and the rightmost pair is associated with the last third of the knob’s trajectory. However, the LEDs being ON or OFF does not correspond with the position of the knob. The principle of this object is to rely on the user’s’ assumptions about correspondence, and subvert those.

For this project, I used:

  • 6 blue LEDs (with cables and 6 330 Ohm resistors)
  • Knob variable resistor (cables and 1 10k Ohm resistor)
  • Cardboard box

The most important part of the box design is to suggest some correspondence between the sensor (knob, soft sensor, etc) and specific bulbs. Secondly, because I couldn’t put the knob in the box, it was important to at least draw it (representation!) so users have an idea of how everything hangs together.