Method and system for automatic factory calibration

Abstract

A sensor may be automatically calibrated during manufacture by providing a sensor processing unit having an integrated sensor, performing a check to determine if the integrated sensor has been previously calibrated upon a reset. When it has been determined the integrated sensor has not been previously calibrated, an automated calibration pattern may be imparted to the sensor so that a calibration parameter is determined.

What is claimed is: 
     
         1 . A method for automatically calibrating a sensor, the method comprising:
 a) providing a sensor processing unit having an integrated sensor;   b) performing a check to determine if the integrated sensor has been previously calibrated upon a reset;   c) monitoring for a machine-induced, automated calibration pattern when the integrated sensor has not been previously calibrated;   d) imparting at least one automated calibration pattern to the sensor processing unit when the integrated sensor has not been previously calibrated; and   e) determining a calibration parameter for the integrated sensor based at least in part on the imparted automated calibration pattern when the integrated sensor has not been previously calibrated.   
     
     
         2 . The method of  claim 1 , wherein the reset comprises an initial power on action. 
     
     
         3 . The method of  claim 1 , wherein performing a check to determine if the integrated sensor has been previously calibrated comprises reading calibration data from a memory location of the integrated sensor. 
     
     
         4 . The method of  claim 3 , wherein the calibration data comprises a factory calibration flag. 
     
     
         5 . The method of  claim 1 , further comprising storing calibration data at a memory location of the integrated sensor. 
     
     
         6 . The method of  claim 5 , further comprising applying the stored calibration data to measurements from the integrated sensor when it is determined the integrated sensor has previously been calibrated. 
     
     
         7 . The method of  claim 1 , wherein monitoring for an automated calibration pattern when the integrated sensor has not been previously calibrated comprises comparing sensor data of the integrated sensor to a predetermined data pattern. 
     
     
         8 . The method of  claim 7 , wherein comparing sensor data of the integrated sensor to the predetermined data pattern comprises determining a difference between the sensor data and the predetermined data pattern and determining the calibration parameter when the difference is below a threshold. 
     
     
         9 . The method of  claim 1 , wherein monitoring for an automated calibration comprises determining a calibration condition accuracy. 
     
     
         10 . The method of  claim 9 , wherein the determining a calibration condition accuracy comprises determining at least one of a variance of a sensor signal, and a ratio between a variance of a sensor signal and a noise level of a sensor signal. 
     
     
         11 . The method of  claim 1 , wherein the automated calibration pattern comprises an initialization sequence. 
     
     
         12 . The method of  claim 11 , wherein the portable device comprises a plurality of types of integrated sensor and wherein a selection of which type of sensor will be calibrated is based at least in part on the initialization sequence. 
     
     
         13 . The method of  claim 12 , further comprising imparting at least one additional calibration pattern to the device and determining a calibration parameter for at least one additional integrated sensor. 
     
     
         14 . The method of  claim 1 , further comprising imparting at least one validation pattern to the sensor processing unit and confirming the determined calibration parameters based at least in part on the imparted validation pattern. 
     
     
         15 . The method of  claim 1 , wherein the automated calibration pattern comprises a predetermined motion. 
     
     
         16 . The method of  claim 15 , wherein the predetermined motion comprises at least one of a rotation, a translation and an acceleration. 
     
     
         17 . The method of  claim 1 , wherein the automated calibration pattern comprises changes in an environmental condition. 
     
     
         18 . The method of  claim 1 , further comprising providing a plurality of sensor processing units, wherein the at least one automated calibration pattern is imparted simultaneously to the plurality of sensor processing units. 
     
     
         19 . The method of  claim 1 , wherein the sensor processing unit is integrated into a portable device. 
     
     
         20 . A portable device comprising:
 an integrated sensor; and   a calibration module configured to:
 a) perform a check to determine if the integrated sensor has been previously calibrated upon a reset of the portable device; 
 b) monitor for a machine-induced, automated calibration pattern when the integrated sensor has not been previously calibrated; and 
 c) determine a calibration parameter for the integrated sensor based at least in part on experiencing the automated calibration pattern when the integrated sensor has not been previously calibrated. 
   
     
     
         21 . The portable device of  claim 20 , wherein the calibration module determines the calibration parameter for the integrated sensor without external communication.