How can I keep the neighbor's dog out my yard?

Ask the owner to keep him out. If that doesn't work, there are leash laws and if the dog is running at large, he can be picked up and put in doggy jail, where his owner will need to pay bail to get him out. Always best to check with your city or township, and give the owner fair warning.

Have you talked with your neighbor? Sounds like they need to keep their dog tied up - or at least supervised. Other than building a fence - there's not much else you can do.

Motion detector water sprayer.

I definitely would try talking to the neighbor first. Good luck!