The utility model relates to the technical field of rainfall sensing, and provides a light
ray rainfall sensor, which comprises a
silica gel pad, a lens, an upper shell, a circuit board and a lower shell, an
infrared transmitter and an
infrared receiver are arranged on the circuit board, the lens is arranged in the upper shell to realize light conduction between the
infrared transmitter and the
silica gel pad and between the
silica gel pad and the infrared
receiver, and the infrared
receiver is arranged in the lower shell. The
light guide side of the lens is provided with a light condensation part and a first reflection part, the light condensation part is arranged on one side, near the infrared receiver, of the infrared
transmitter, the light condensation part is in a convex mirror shape, and the convex surface of the light condensation part faces the infrared transmitter; the first reflecting part is arranged on the side, far away from the infrared receiver, of the infrared transmitter, the first reflecting part is in an arc shape, an arc opening of the first reflecting part faces the infrared transmitter, the inner arc face of the first reflecting part is a
refraction face, and the outer arc face of the first reflecting part is a reflecting face. According to the lens, the first reflecting part is arranged on the
light guide side, the inner arc surface of the first reflecting part is the refracting surface, and the outer arc surface of the first reflecting part is the reflecting surface, so that the alignment requirement of the infrared transmitter and the light condensing part is reduced.