Problem implementing ultrasonic interrupt (new ping library)

GreyE30:
Thats great Tim, thanks for the pointers and email reply. A real help for possible direction to start looking.

I hope I can get this reviewed and improved soon.

The camera uses SPI, which is uses pins 10-13. You're also trying to connect the ultrasonic sensor to pins 11 and 12. So, you have two things wired to the same pins, which of course will cause a problem. Always know what pins a shield uses and always try different pins if you ever have a problem. Even if a shield isn't connected to a pin, it could use a timer that's tied to a pin which could cause a conflict.

Tim