ProblemMessure on cm about arduino-new-ping HOT 6 CLOSED

Finally i change on the NewPing.h the bellow:

#define US_ROUNDTRIP_CM 29 //57      // Microseconds (uS) it takes sound to 
travel round-trip 1cm (2cm total), uses integer to save compiled code space.

And now measure correct, please confirm if that effect only to this 
sonar.ping_cm() or it is for other subs too.

Thank you in advance.

Best Regards,
Tasos

You changed US_ROUNDTRIP_CM from 57 to 29 and your result is now 10cm instead 
of 5cm but your modification is wrong because sound needs more than 29 
microseconds to travel 2cm.

Testing NewPing and Ultrasonic I get different values. Ultrasonic result is 
correct (299cm) but NewPing is wrong (306cm). If I change US_ROUNDTRIP_CM from 
57 to 58 I get the same result with both libraries.

It depends on your temperature.  For me, 57 is more accurate which is why it's 
the default.  I made it easily user configurable so each user could set the 
value they wanted for their environment.  Also, if accuracy is something you 
need, you shouldn't be using the ping_cm() method at all.  It's designed to be 
quick, small, and accurate for most people.  But, if you need better accuracy, 
use the ping() method, a temperature sensor, and your own logic to convert time 
to distance based on the current temperature, altitude, humidity, etc.

[deleted comment]

Please report this in a more appropriate place.