Using NewPing with HC-SR04s on UNO

I am trying to properly use the NewPing Library to utilize some HC-SR04s that I want to use for my rover project.

My issue is when using the the ping_timer method.

When there are no objects in the path of the sonar, i inconsistently get returns from check_timer method, every so often. The ping_result is set to a seeming bogus, but inconsistent value.

When there is an object int he sonars path I get frequent seemingly correct results.

After an obstruction to the sonar has been detected, then it is taken away, then I rarely get a return from check_timer, which I am guess mean that the echo time max was surpassed (no echo).

How can I tell when a return from check_timer is the result of a no echo situation and when its not?

Thanks for any help,
-Ryan

Hi Ender1618,

Alternative(s) to NewPing Library is considered?
The code in this link worked with HC-SR04s on UNO, give it a try.
http://arduinobasics.blogspot.my/2012/11/arduinobasics-hc-sr04-ultrasonic-sensor.html