Compensating accelerometer with optical angle sensing

A compensating accelerometer comprising:

• a housing;
• a pendulum within the housing flexibly coupled to a base,
• wherein the pendulum includes a coil mounted on a movable plate and a curtain having an opening;
• a light source and a differential light detector generating a signal proportional to angular displacement of the pendulum;
• a magnet magnetized in a direction of an axis of the pendulum;
• a magnetic conductor that, together with the coil and the magnet, is used to return the pendulum to a neutral position;
• a feedback circuit generating an output proportional to acceleration experienced by the compensating accelerometer based on the angular displacement of the pendulum;
• and
• a load mass affixed to the curtain.

A compensating accelerometer comprising:

• a housing;
• a pendulum within the housing flexibly coupled to a base,
• wherein the pendulum includes a coil mounted on a movable plate and a curtain having an opening;
• a light source and a differential light detector generating a signal proportional to angular displacement of the pendulum;
• a magnet magnetized in a direction of an axis of the pendulum;
• a magnetic conductor that, together with the coil and the magnet, is used to return the pendulum to a neutral position;
• a feedback circuit generating an output proportional to acceleration experienced by the compensating accelerometer based on the angular displacement of the pendulum;
• and
• a second feedback circuit that compensates for temperature effects that distort the output.

A compensating accelerometer comprising:

• a housing;
• a pendulum within the housing flexibly coupled to a base and including a movable coil, the movable coil being symmetrical about a suspension axis of the pendulum;
• a light source;
• a differential photodiode serving as current source and generating a signal proportional to angular displacement of the pendulum, the signal based on light received from the light source;
• a magnet magnetized in a direction of an axis of the pendulum;
• a magnetic conductor that, together with the coil and the magnet, is used to return the pendulum to a neutral position;
• means for mechanical tuning of a zero bias of the accelerometer;
• and
• a circuit generating an output proportional to acceleration experienced by the compensating accelerometer based on the angular displacement of the pendulum.