Farm Alarm

Hello I am trying to protect goats with a PIR sensor and alarm, but am having problem with the bluetooth speaker.

A neighbor recently found 4 adults and one newborn goat pleasure killed by a pack of wild (feral) dogs and I am resolved to figure out an alarm that would drive away these pests without having to pull all nighters posting up with guns waiting for these poochies. Then I can make a few for the local farmers and hobby ranchers to help them out as well.

So far I have worked out the use of PIR sensors around the pen that are working great with my off-brand mega board, both of which were easily available from a nearby Fry's Electronics. However I'd like to implement either a loud noise or a high pitch noise to drive away these dogs. As I'm a newcomer to Arduino in general, I couldn't really get a speaker or buzzer that would both meet my standards and the board's capability for output. I got a Bluetooth transmitter with a Bluetooth speaker to compensate for that problem, but am a bit confused on how to proceed as I can't find much info online about folks using a Bluetooth speaker as an output. The issue I'm having is that I can't connect the transmitter to the speaker.

My only experience with electronics is with remodel construction and wiring my own home. My only arduino experience is a few sensors with my aquaponics plants so far but this is my first major effort. Have any of you folks had success with using bluetooth in your alarms for your IoT systerms? Hope I'm posting in the right area. Will appreciate any help and have a fantastic day :slight_smile:

I would just use an audio amplifer, wired between the Arduino and a normal speaker. This Class D amplifier is small, powerful and very efficient.

Or you could use a regular burglar alarm horn with a built in oscillator. You may need a relay or MOSFET to control the power to the horn from the Arduino. This one comes with a PA microphone.

I'd tend to agree some with the use of an amp but...

Last Xmas I bought some decorations that played the same Xmas song over and over again. We soon got bored of that song so I bought a couple of basic MP3 players off of eBay and installed them in the decorations in place of the circuit that was in them.

I loaded a micro SD card with a load of Xmas songs and used an Arduino nano to contol the player via a RF link.

Unless you wanted to use one the RF link is not needed as the Arduino and PIR you are using could control the MP3 player directly.

Search for GPD2846A on eBay. Cheap MP3 player and very controllable from an Arduini.

They are loud (depending on background noise obviously) but if needs be can be beefed up by a more powerful amp.
Using the MP3 player and Arduino would allow you to control the on / off times and let you load a micro SD card with different sounds to see which works the best without having to change anything or just cycle through them to prevent the dogs getting used to one sound and ignoring it.

Regards