Alternative Text for Figure 1:

The first photo in figure one is a Solid Works model of the rear bumper and electronics box. The box is a simple square box with holes in the side for connectors and a thin lid. The box sits atop two beams that attach to the underside of the wheelchair. Attached to these beams are telescoping tubes leading to the rear bumper. The rear bumper consists of two moving bars that are interfaced to one bar featuring switches. A force applied to one of the bumpers presses a switch that activates the system. The second photo shows a Solid Works model of bumpers designed to interface with the foot rest of the wheelchair. Two plates provide an attachment mechanism by clamping to the top and bottom of the foot rest. Again there are two bumper pieces that pivot about the center and press switches when enough force is applied.