Gravity: URM09 Analog Ultrasonic Sensor DFRobot URM09 Analog Ultrasonic Sensor is designed for fast-ranging and obstacle avoidance applications with the measuring frequency of up to 30Hz. This ultrasonic sensor adopts built-in temperature compensation and analog output. The URM09 sensor can provide accurate distance measurement within 2cm to 500cm with 1cm resolution and ±1% accuracy. This sensor is compatible with Arduino, Raspberry Pi, and other main-control boards with a logic level of 3.3V or 5V. Typical applications include backing car annunciator and doorbell.