Abstract: A system for detecting velocity airflow in a duct includes a plurality of vortex shedders arranged within the duct for inducing the shedding of vortices at a corresponding plurality of selected locations at a frequencies related to the airflow in the duct and a sound-sensing location on each vortex shedder. A plurality of microphones, each microphone being coupled acoustically with each sound-sensing location senses sounds generated by said shedding of vortices in a corresponding passage and provides an information signal indicative of said vortex shedding sounds. A processing unit performs a Fast Fourier Transform on the information signals to determine frequency of maximum amplitude within the information signals.

Abstract: A system for detecting velocity airflow in a duct includes a plurality of vortex shedders arranged within the duct for inducing the shedding of vortices at a corresponding plurality of selected locations at a frequencies related to the airflow in the duct and a sound-sensing location on each vortex shedder. A plurality of microphones, each microphone being coupled acoustically with each sound-sensing location senses sounds generated by said shedding of vortices in a corresponding passage and provides an information signal indicative of said vortex shedding sounds. A processing unit performs a Fast Fourier Transform on the information signals to determine frequency of maximum amplitude within the information signals.

Abstract: A system and process for controlling power delivered to an electrical load, such as lighting system, to controllably effect operation of the load (e.g., intensity of illumination). In at least some embodiments, the system and process interpret a user-adjustable setting of a typical electronic low voltage (ELV) dimmer control device that is otherwise isolated from facility AC power. An electrical stimulus, such as a relatively low power AC or DC voltage, is applied at one or more externally accessible terminals of the ELV dimmer control. An electrical response of the dimmer control to the stimulus is measured at one or more externally accessible terminals of the dimmer control. The electrical response varies according to the applied electrical stimulus and a user-adjustable setting of the dimmer control. An indication of the setting of the user-adjustable control is determined from the measured electrical response, and used to correspondingly dim a lighting source.

Abstract: A system and process for controlling power delivered to an electrical load, such as lighting system, to controllably effect operation of the load (e.g., intensity of illumination). In at least some embodiments, the system and process interpret a user-adjustable setting of a typical electronic low voltage (ELV) dimmer control device that is otherwise isolated from facility AC power. An electrical stimulus, such as a relatively low power AC or DC voltage, is applied at one or more externally accessible terminals of the ELV dimmer control. An electrical response of the dimmer control to the stimulus is measured at one or more externally accessible terminals of the dimmer control. The electrical response varies according to the applied electrical stimulus and a user-adjustable setting of the dimmer control. An indication of the setting of the user-adjustable control is determined from the measured electrical response, and used to correspondingly dim a lighting source.

Abstract: A system for controlling power delivered to a lighting system for controlling illumination. The system includes a TRIAC with an input capacitor connected in parallel to a phase delay circuit including a series combination of a potentiometer and a capacitor. A ramp voltage output from the timing circuit is connected through a DIAC to a gate input of the TRIAC. The TRIAC is connected between a DC voltage source and an electrical load. In response to the DC source, the input power storage capacitor, the phase delay timing circuit and the input terminal of the TRIAC have a direct current output voltage higher than a DIAC breakover voltage, used to drive a gate input of the TRIAC. The TRIAC operates in relaxation oscillation mode such that a frequency of oscillation of the TRIAC circuit, as controlled by the timing resistor, can be used to control power to the electrical load.