A system may have a mobile device having at least two wheels and a distance measuring device configured to be removably attached to a frame of the mobile device, which can be a mobility assistance device, such as a walker and a wheelchair. The distance measuring device may have at least a sensing mechanism, an accumulator, and a display that are in communication with one another, with the sensing mechanism configured to monitor rotation of the at least one of the at least two wheels of the mobile device and the accumulator configured to determine the distance traveled by the mobile device based on this rotation and output the distance result on the display.
