The HC-SR04 ultrasonic sensor uses sonar to determine the distance to an object like bats or dolphins do. It offers excellent range accuracy and stable readings in an easy-to-use package. It operation is not affected by sunlight or black material like Sharp rangefinders are (although acoustically soft materials like cloth can be difficult to detect). 

• Power Supply :5V DC
• Quiescent Current : <2mA
• Effectual Angle: <15°
• Ranging Distance : 2cm – 500 cm/1" - 16ft
• Resolution : 0.3 cm