M5Stack UNIT SONIC IO is a GPIO interface ultrasonic range sensor with an RCWL-9620 ultrasonic distance measurement chip. This sensor determines the distance to a target by measuring time lapses between the transmitting and receiving of the pulse signal. The UNIT SONIC IO sensor features a 16mm probe and a range accuracy of 2cm to 450cm. The distance value can be obtained through the IO control mode. This sensor offers built-in temperature compensation for reduced temperature drift. Typical applications include robot obstacle avoidance, fluid level detection, and sitting posture detection.