I know there are a lot of products out there to ward off pests.
I can NOT find a description of the sound that cats, dogs, and deer hate. Certainly it will vary. I just want to be able to "say" my jack-o-lantern deters animals who will eat it. A deer ate neighbors! I already have ESP32 making the flickering light reminisent of a candle but pissed off i can't find data on ultrasonic deterence of animals.
Cats: Every xxx seconds, emit a pulse of yyy hertz for zzz ms.
Dogs: "" "" ""
Deer: "" "" ""
See what I mean? It does NOT have to be foolproof or effective. Pissing contest only.
If you want to find out what commercial products use, use a Google search phrase that contains the word 'patent', for example 'patent ultrasonic repeller Hz'. Add the animal of choice to narrow the range of results.
Build one of those (the circuit is really simple), and trigger it by a motion sensor. PIR comes to mind.
The moment there's motion nearby, the "alarm" goes off. One or more pulses of sound. Some 25 kHz may work well to scare off the animals (a quick Google search tells me deer can hear up to some 30 kHz; dogs up to some 45 kHz; cats almost double that - but invariably sensitivity goes way down at high frequencies). With amplification you may even push it to as loud as 110 or 120 dB.
Set it to 17, 18 kHz and it'll also keep the local youth at bay
That circuit is rather clever. LC oscillator with MOSFET driver as both inverter and amplifier.
My wife is a biologist. Like you I wanted to build something to keep squirrels out of our cherry tree. She responded that "critter chasers" advertised in Popular Mechanics and other magazines (usually with a male audience) are bunk.
Critters from chipmunks to bears are startled by sudden noise that they haven't heard before. Most will leave the area. But over time- a few hours or days, they become accustomed to the noise and since no harm comes from it, they ignore it. Note all the wildlife in our neighborhood just a few hundred feet from a freeway. We have had wild turkeys, deer and a confirmed bear. The freeway noise bothers me more than them.
SteveMann:
Critters from chipmunks to bears are startled by sudden noise that they haven't heard before. Most will leave the area. But over time- a few hours or days, they become accustomed to the noise and since no harm comes from it, they ignore it. Note all the wildlife in our neighborhood just a few hundred feet from a freeway. We have had wild turkeys, deer and a confirmed bear. The freeway noise bothers me more than them.
Yeah... I kinda was just toying with the idea so I could say I had a critter-proof jack-o-lantern (in addition to it being wifi). Funny - I can ping it but it's not showing in IDE as a port....
