A lamp that includes a lens, an electrode, and a sensing circuit connected to a light source. The lens is spaced apart from the sensing circuit. The forward facing surface of the lens has a sensing location. The electrode has a first portion opposite a second portion. The first portion is connected to the sensing circuit. The second portion is positioned alongside a backward facing surface of the lens. The electrode senses an electric field through the lens at the sensing location. The sensing circuit is configured to turn on the light source when the light source is turned off and the electrode senses the electric field. The sensing circuit is configured to turn off the light source when the light source is turned on and the electrode senses the electric field.