An optical imaging lens includes, from an object side to an image side, an aperture stop, first, second, third, fourth, and fifth lens elements. The flexible touch sensor detects whether the at least one armrest is grasping by a person; if no, the processor controls the acceleration sensor to detect whether the smart stroller is moving. The inner space is divided into multiple chambers that communicate with each other. In another embodiment, the housing structure also covers substantially all of the interposer edge surfaces. The orthohydroxyarylaldoximes, or orthohydroxyarylketoximes commonly are of Formula, . Due to the resulting zero DC level and minimum reverse bias voltage over the duty-cycle adjustable range, the duty-cycle adjustable clock generator can be effectively used in various microwave and optical communication systems.