A Diffuse Reflective Light Curtain System comprises at least one light curtain defining a border of a work zone for a robotic machine. Each light curtain comprises a primary board having multiple wells formed therein. Light emitting diodes (LEDs) and light detectors are alternately placed in the multiple wells. The LEDs shine light up from the wells to form a curtain of light above the primary board. If an object comes into contact with the curtain of light emitted from the LEDs, the light is reflected back to toward the board and enters the wells of the board where the light detectors sense the presence of LED light. When the light detectors in the wells sense the presence of LED light, they send a signal to a controller to indicate that the light curtain has been breached by a foreign object. The controller, in turn, suspends the operation of the robotic machine that is protected by the light curtain. If multiple light curtains are used to define a plurality of work zones, sensors may be connected to the controller to determine the physical position of the robotic machine. The controller selectively enables or disables each of the light curtains based upon inputs received from the sensors to allow for foreign objects to enter particular work zones at different times during the operation of the robotic machine.