I'm thinking of adding a wind speed measurement device to my house monitoring system and I was wondering if anybody can point me to a formula that relates the wind speed to the RPM of the "vane". I am using the device with several "cups" connected to a bar that rotates in response to wind. Thanks for any pointers. TTYL -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu