Treadmill parts — the rollers, rails, motor, and heart rate monitor — can serve other purposes once you're done using them as a treadmill. My father gave me his used treadmill before he died. I had ...

Steven Devor, front, developed the automated treadmill using off-the-shelf parts, including an inexpensive sonar range finder and an existing treadmill. (Photo by Jo McCulty, Courtesy of Ohio State ...