An inclinometer based on free convective motion of a heated air mass

Abstract

In this application a thick-film tilt sensor has been developed based on heat transfer by natural convection. The device measures internal changes in heat transfer caused by the inclination using the force of gravity as an input. The device is functionally equivalent to traditional proof-mass accelerometer. The proof mass in the new thick-film sensor is a gas. The gaseous proof-mass provides great advantages over the use of the traditional solid proof mass. A conditioning electronics amplifies the signal variation induced by the inclination compensating the deviation due to the initial asymmetrical values of the bridge arms and their slow variations. Preliminary tests on the first prototypes show an accuracy of about 2% fall scale output, repeatability of about 0.2/spl deg/ and resolution better than 0.1/spl deg/ over a /spl plusmn/20/spl deg/ range.