I see posts from time to time wanting a siren controlled by home automation. I tried several "home automation" sirens but they were all feeble. For instance:
Dome Home Automation DMS01 Wireless Z-Wave Battery-Powered Home Security Siren and Chime, White
Aeotec Siren Gen5, Z-Wave Plus, 105dB Siren with Strobe alerts, Plug-in, Backup Battery
What I was looking for was something to encourage any critters that found their way into the shop to leave so needed something LOUD. What I found was the Honeywell Ademco 748 119db Dual-Tone Siren.
You do not want to be in the room with this going off without ear protection. To power it I'm using the BINZET DC12V 2.5A 30 Watt LED Power Supply Driver Transformer AC 120V-130V to DC 12V 2.5A Output Voltage Convertor LED Strip Low Voltage Powered LED Light Regulator.
All you then need is to stick it into any smart plug you have. The Etekcity WiFi Smart Plugs are a cheap and simple solution for it. The VeSync app makes it simple to control without automation too.