AD9850Ultrasonic_Deterrent by ptamike

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Silent but Deadly! A powerful but simple ultrasonic cat deterrent that's silent to humans. This device uses an AD9850 DDS module coupled with a Class D audio amplifier to emit a siren-like tone that sweeps a sinewave between 20kHz and 24kHz for 20 seconds every 4 minutes. In between alerts, the Arduino goes into sleep mode and also puts the connected class D PA into sleep mode. The sinewave output is taken from the DDS board and Digital pin 6 provides the drive for a flashing LED Strobe whilst pin 7 provides a shut-down signal (pin LOW) for an attached class-D amplifier. A simple power source used for the prototype is 4 x AA rechargeable batteries with a 5V boost/buck regulator. The current consumption will primarily depend on the speaker load. I used 2 pairs of Piezo tweeters that presented a 50 ohm load at 22kHz. The use of a voice-coil tweeters will increase the consumption.