NewPing Library: HC-SR04, SRF05, SRF06, DYP-ME007, Parallax PING))) - v1.7

Using Arduino Sensors
415

I got a lot of bad readings. Is it normal?
Something like this....

Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 185cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 186cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 187cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 185cm
Ping: 185cm
Ping: 180cm
Ping: 185cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 185cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm
Ping: 0cm