Acoustic occupancy sensor

An occupancy sensor, comprising:

• an acoustic transmitter;
• an acoustic receiver comprising:
• an acoustic sensor;
• a pre-amplifier operably coupled to the acoustic sensor comprising a digital potentiometer, wherein the digital potentiometer is adapted to control the gain of the pre-amplifier to prevent clipping of signals received by the acoustic receiver;
• and
• an analog to digital converter operably coupled to the pre-amplifier;
• a demodulator operably coupled to the acoustic receiver;
• a variable bandpass filter operably coupled to the demodulator comprising:
• a digital potentiometer adapted to control a gain of the bandpass filter;
• a digital potentiometer adapted to control a tuning of the bandpass filter;
• and
• a digital potentiometer adapted to control a ratio of a center frequency of the bandpass filter to a bandwidth of the bandpass filter;
• and
• a controller operably coupled to the acoustic transmitter, the acoustic receiver,
• the demodulator, and the variable bandpass filter comprising:
• a pre-amplifier engine adapted to control the acoustic receiver;
• a bandpass filter engine adapted to control the variable bandpass filter;
• a doppler shift engine adapted to characterize the signals filtered by the variable bandpass filter;
• and
• an occupancy sensing engine adapted to characterizations of the Doppler shift engine to determine the presence of absence of the occupant within the defined region;
• wherein the controller is adapted to:
• transmit acoustic signals using the acoustic transmitter,
• receive acoustic signals using the acoustic receiver,
• process the received acoustic signals using the demodulator,
• filter the processed acoustic signals using the variable bandpass filter, and
• process the filtered acoustic signals to determine the presence or absence of an occupant within a defined region.

A method of operating an occupancy sensor, comprising:

• transmitting acoustic signals into a defined region;
• receiving acoustic signals from the defined region;
• filtering the received acoustic signals using a variable bandpass filter;
• and
• processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

A method of operating an occupancy sensor, comprising:

• transmitting acoustic signals into a defined region;
• receiving acoustic signals from the defined region;
• converting the acoustic signals into electrical signals;
• amplifying the electrical signals without clipping the electrical signals;
• filtering the received acoustic signals using a variable bandpass filter;
• controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;
• sweeping the variable bandpass filter upwardly along a range of frequencies;
• then sweeping the variable bandpass filter downwardly along a range of frequencies;
• time averaging an amplitude of the filtered acoustic signals;
• comparing the time averaged amplitudes of the filtered acoustic signals;
• determining if a filtered acoustic signal indicates a source of noise within the defined region;
• and
• determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.

A system for operating an occupancy sensor, comprising:

• means for transmitting acoustic signals into a defined region;
• means for receiving acoustic signals from the defined region;
• means for filtering the received acoustic signals using a variable bandpass filter;
• and
• means for processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

A system for operating an occupancy sensor, comprising:

• means for transmitting acoustic signals into a defined region;
• means for receiving acoustic signals from the defined region;
• means for converting the acoustic signals into electrical signals;
• means for amplifying the electrical signals without clipping the electrical signals;
• means for filtering the received acoustic signals using a variable bandpass filter;
• means for controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;
• means for sweeping the variable bandpass filter upwardly along a range of frequencies;
• means for then sweeping the variable bandpass filter downwardly along a range of frequencies;
• means for time averaging an amplitude of the filtered acoustic signals;
• means for comparing the time averaged amplitudes of the filtered acoustic signals;
• means for determining if a filtered acoustic signal indicates a source of noise within the defined region;
• and
• means for determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.

A computer program for operating an occupancy sensor, comprising program instructions for:

• transmitting acoustic signals into a defined region;
• receiving acoustic signals from the defined region;
• filtering the received acoustic signals using a variable bandpass filter;
• and
• processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

A computer program for operating an occupancy sensor, comprising program instructions for:

• transmitting acoustic signals into a defined region;
• receiving acoustic signals from the defined region;
• converting the acoustic signals into electrical signals;
• amplifying the electrical signals without clipping the electrical signals;
• filtering the received acoustic signals using a variable bandpass filter;
• controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;
• sweeping the variable bandpass filter upwardly along a range of frequencies;
• then sweeping the variable bandpass filter downwardly along a range of frequencies;
• time averaging an amplitude of the filtered acoustic signals;
• comparing the time averaged amplitudes of the filtered acoustic signals;
• determining if a filtered acoustic signal indicates a source of noise within the defined region;
• and
• determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.