Here is a tiny gadget that can stop dogs barking around your property. The KCSC Mini Anti Barking Device has a sensitive microphone to pick up barking up to 50 feet away. It blasts high-pitched sounds that only dogs can hear to get the job done. The device has 3 levels, with ranges from 15 to 50 feet.
The device can be easily hung from a tree. It is available for under $39 at this time.