Abstract: The invention pertains to apparatus for sensing the motion of endless conveyors. A housing, on which a traction wheel having a high friction periphery is rotatably mounted, is located adjacent the moving conveyor member to be sensed, and the housing includes an open end through which a portion of the wheel periphery extends for engagement with the moving member. The wheel rotates a shaft which is belted to the input shaft of a motion sensor, preferably of the electrical type, mounted upon the housing. In one embodiment of the invention the traction wheel is adjustably mounted upon the housing whereby adjustment of the wheel to the moving member is facilitated. In another embodiment the wheel housing is of an elongated configuration utilizing a mounting bracket which may be affixed to the housing at the desired position to accommodate the dimensions of the particular installation.