A sensing device, comprising: an electromagnetic sensor having a surface with at least one electromagnetic radiation interception area; at least one analog signal processor connected to said electromagnetic sensor and adapted to: receive an analog signal from said electromagnetic sensor, to produce a resulting signal having at least one amplitude when said electromagnetic sensor intercepts radiation from a detected object in said at least one electromagnetic radiation interception area; perform a determination of whether a movement of a person or a pet is detected according to a comparison between said resulting signal and a predetermined amplitude threshold; and deliver an output indicative of said determination; wherein a transfer function is applied to the analog signal received from said electromagnetic sensor when intercepting radiation from a person or a pet animal at a frequency dependent on the detected object's distance from said electromagnetic sensor to each of said person or pet animal, to produce a resulting signal having a first substantially constant amplitude when said electromagnetic sensor intercepts radiation from said person, and a second substantially constant amplitude when said electromagnetic sensor intercepts radiation from said pet animal, characterized in that each of said first and second amplitudes of the resulting signal is substantially constant regardless of the detected object's distance from the sensor within an operational range of frequencies. an electromagnetic sensor having a surface with at least one electromagnetic radiation interception area; at least one analog signal processor connected to said electromagnetic sensor and adapted to: receive an analog signal from said electromagnetic sensor, to produce a resulting signal having at least one amplitude when said electromagnetic sensor intercepts radiation from a detected object in said at least one electromagnetic radiation interception area; perform a determination of whether a movement of a person or a pet is detected according to a comparison between said resulting signal and a predetermined amplitude threshold; and deliver an output indicative of said determination; wherein a transfer function is applied to the analog signal received from said electromagnetic sensor when intercepting radiation from a person or a pet animal at a frequency dependent on the detected object's distance from said electromagnetic sensor to each of said person or pet animal, to produce a resulting signal having a first substantially constant amplitude when said electromagnetic sensor intercepts radiation from said person, and a second substantially constant amplitude when said electromagnetic sensor intercepts radiation from said pet animal, characterized in that each of said first and second amplitudes of the resulting signal is substantially constant regardless of the detected object's distance from the sensor within an operational range of frequencies. receive an analog signal from said electromagnetic sensor, to produce a resulting signal having at least one amplitude when said electromagnetic sensor intercepts radiation from a detected object in said at least one electromagnetic radiation interception area; perform a determination of whether a movement of a person or a pet is detected according to a comparison between said resulting signal and a predetermined amplitude threshold; and deliver an output indicative of said determination; wherein a transfer function is applied to the analog signal received from said electromagnetic sensor when intercepting radiation from a person or a pet animal at a frequency dependent on the detected object's distance from said electromagnetic sensor to each of said person or pet animal, to produce a resulting signal having a first substantially constant amplitude when said electromagnetic sensor intercepts radiation from said person, and a second substantially constant amplitude when said electromagnetic sensor intercepts radiation from said pet animal, characterized in that each of said first and second amplitudes of the resulting signal is substantially constant regardless of the detected object's distance from the sensor within an operational range of frequencies.