The ultrasonic sensor 2 can be used to detect the distance between an obstacle and it. The transmitter on the left transmits ultrasonic waves, and the receiver on the right receives the ultrasonic waves reflected. Compared to the ultrasonic sensor we've developed before, the ultrasonic sensor 2 is improved in its casing, chip, and blue LEDs. The blue LEDs can increase the potential for emotional expression and interaction. *Specifications : Output range: 5–300 cm (The output value is 300 when the distance detected is out of the output range.) Output value error: ±5%