Wall hollowing detection device

The utility model discloses a wall hollowing detection device, which comprises a knocking assembly and a moving assembly for driving the knocking assembly to move, the knocking assembly comprises a fixed block, the bottom end of the fixed block is rotatably connected with a rotating rod, the bottom end of the rotating rod is fixedly connected with two elastic rods in a Y shape, and the elastic rods are fixedly connected with the fixed block. Knocking balls are arranged at the bottom ends of the two elastic rods, an annular ring is fixedly connected to the lower portion of the fixing block, and a triangular tooth groove is formed in the annular ring. The directional wheel drives the rotating rod to rotate through the transmission assembly, the rotating rod rotates to drive the elastic rod and the knocking ball to do axial movement and is matched with the triangular tooth groove of the annular ring, when the elastic rod rotates to the tooth peak of the triangular tooth groove, the knocking ball knocks the wall