Tilt sensor and method of forming such device

An apparatus for use as a sensor for detecting the angle of inclination of a body relative to a reference position, the apparatus comprising:

• a substrate affixed within the body and in electrical communication with an input voltage;
• a first portion of the substrate adapted to deflect in response to an applied pressure on the substrate;
• a weight disposed on an upper surface of the substrate, the weight adapted to exert the applied pressure when the body is at an angle of inclination relative to the reference position;
• a plurality of piezoresistors disposed within the first portion and adapted to generate at least one output voltage signal in response to the first portion of the substrate deflecting;
• and
• means for reading the at least one output voltage signal, the at least one output voltage signal being indicative of the angle of inclination.

A method for detecting the angle of inclination of a body relative to a reference position comprising the steps of:

• providing a substrate at least a portion of which will deflect in response to the application of a pressure;
• determining the areas of maximum stress in the substrate caused by the pressure;
• forming a plurality of piezoresistors within the substrate proximate the areas of maximum stress, the plurality of piezoresistors forming a Wheatstone bridge circuit that will generate at least one output voltage signal in response to changes in resistance of the piezoresistors;
• affixing a weight to an upper surface of the substrate, the weight adapted to exert the pressure when the substrate is at an angle of inclination relative to the reference position;
• providing an input voltage to the substrate;
• and
• reading the at least one output voltage signal, the at least one output voltage signal being indicative of the angle of inclination.