For the neighbor's dog. Heard about the ultrasonic noisemakers that are triggered by a dog's bark, but at $50 and several unfavorable comments, thought I'd try to roll my own.
Aiming for 16-20 kHz. In a bit of a hurry at the moment, so no C, R1 and R2 chosen yet, but is this a good idea? I've got a couple spare
12V lead acid batteries lying about, and a couple of spare 4 ohm car speakers (10 watt max), so I'm thinking of using them to amplify a square wave:Any comments on this circuit? Should I put a cap between the +12V and the speaker?
--------------------------[switch]-- + 12V | | | | | _ / |-- |_| 4 ohm speaker | | \\ -------- | | 8 4 | | | | | | 555 | D | 3|----47R----G IRF530 MOSFET | | S | 1 | | -------- | | | | | -------------------------------- GND