Random large negative numbers output from ultrasonic sensor arduino

Using Arduino Sensors
1

Hi all;

I am new to arduino and I am testing a sample ultrasonic sensor based project. I have 2 ultrasonic sensors, one that is giving correct numbers, the other is giving random large negative numbers randomly (doesn't respond to any changes done at the input side). I want to know if this is a manufacturing error (malfunction) at the sensor side or what other possibilities for this issue?

2

How are you powering the sensors? Less than the required voltage can result in unusual behavior. My PING sensor, for example, just doesn't do its thing at voltage much below the 5v it wants.