Look for us around 3AM. 
 
I don't know what day, but just keep looking.

 And this one won't do anything else -- except to meditate.
 
 

 Oh look, Beagle is at the door.
 
Hehehehe that wink says it all... we know what he's come for.....
 
 
The BECON!!!
 
 

If you want to be certain that it isn't a person.
Put a light dusting of powder, flour will work, use a sifter and get a very light dusting. No rain or wind when you do it. When the bell rings go look for footprints. If you find some footprints, go get a big can of glue like exterminators use to make big glue boards. Spread it on a big piece of cardboard and put it on the porch and hope that someone legit like the police don't show up for anything and keep your dog or cat inside. If you do that, the more they struggle the more stuck they will get. Baby oil will work it loose from fur or skin. Then again, these days.. you would probably get sued and the criminal would win. At least the dusting will tell you for sure if it is or is not someone.
I think it is probably a faulty unit or faulty wiring though, like some said. I hate Chinese batteries and it is getting where more and more are made in Chia or Viet Nam. I bought one of those really big packs of 9v and a big pack of AA batteries, the Utilitech brand from Lowes. In less than a year nearly half of the AAs were leaking and the 9v had a problem that one of the poles would snap off if I tried to replace it. They were REALLY bad batteries. I don't know how anyone could make batteries that poorly. Maybe they are the same people who now make "gold toe" socks and cannot make two socks that are the same length. The slave labor is really falling down on the job.
 

There's the country variant, "You're ringin' my bell, but there ain't nobody home."

My Ding-a-ling?
Oh, nevermind...

It's worse when the doorbell rings and there is someone there.