| abstract |
A pest deterrent device attracts the attention of a pest with ultrasonic noise and then produces a series of flashes to drive off the pest. In one embodiment, the device continuously produces ultrasound, changing the ultrasound when a pest is detected. In another embodiment, the device does not produce ultrasound until a pest is detected. In a further embodiment, the flash charging circuit is used to modulate the ultrasound while the flash is operated. In a particular embodiment, four ultrasonic speakers are arranged in a series-parallel configuration with a total capacitance of about 0.2 micro-Farads achieve 120 dB of sound output with a supply voltage of about 12-18 V. |