A robotic device having a body with an upper surface resiliently connected to a lower surface and having a bump sensor including a contact point on the lower surface, which contact pint is in its normal position when centrally located within a sensor device, which is an aperture having a conducting inner periphery, which sensor device is located in the upper surface of the robotic device, so that a bump on the upper surface is detected by the robotic device when the contact point abuts the aperture conducting inner periphery. The robotic device also includes a drop sensor for use in association with the lower surface of the robotic device with the lower surface having a periphery around which a plurality of drop sensors are located, with each drop sensor including a body located therein, a movably vertically oriented member, so that when any such member becomes positioned over a drop in terrain, the vertically oriented member will drop downwardly and trigger the production of a signal which is sensed by the robotic device.