An obstacle-detectable mobile robotic device includes a frame body capable
of traveling on a surface, a control circuit mounted to the frame body
for controlling the traveling manner and direction of the frame body, and
a detection system mounted to the frame body and electrically connected
with the control circuit. The detection system has an optical emitter, an
optical receiver, and a reflector. The optical emitter emits the light
onto the surface, and the light is reflected onto the reflector and then
to the optical receiver to be received by the optical receiver. A
receiving area generated by the optical receiver on the reflector never
overlaps the surface. Accordingly, the obstacle-detectable mobile robotic
device can effectively avoid ambient light pollution to have preferable
detection potency.