reader [Joshua] sent in his most current project. using a sonar rangefinder, an Arduino, and some creative programming, he’s made is computer react to his distance from it. As you can see in the video after the jump, he has programmed it to change text size and background color depending upon his distance from the screen. While he admits that his application doesn’t seem right away useful, there’s lots of potential there. We can actually think of several uses. What would you use it for?