Inventors:
Richard Stephen Pollack - Boulder CO
Dale Lee Yones - Boulder CO
Robert Walter Brown - Medina OH
Assignee:
The Goodyear Tire Rubber Company - Akron OH
International Classification:
G01C 1900
Abstract:
A method ( ) of calibrating a transponder ( ) capable of measuring temperature data (N ) and pressure data (N ) in an object (e. g. , a tire, ( )) and transmitting a data stream (FIG. C) to an external reader/interrogator ( ). The transponder includes memory ( ) for storing measurements, calibration data ( ), transponder ID number and the like. Since the transponder combines temperature and pressure information in the âpressureâ data, the ratio N /N is a direct indicator of pressure only, and is also relatively insensitive to transponder power variations. The calibration method employs a calibration chamber ( ) containing reference pressure ( ) and temperature ( ) sensors. The transducer to be calibrated is placed in the chamber and exposed ( ) to a number of predetermined temperatures and pressures (as measured by the reference sensors) at a number of calibration points. At each calibration point, a temperature reading (N ) and a pressure reading (N ) sensed by the transponder are recorded along with the reference temperature and pressure. Prom these readings and reference measurements the calibration constants (N , m , N /N , m ) are calculated ( ).