I'm just rolling this around in the back of my head for a project.

I live in a rural area and we have problems with hunters driving through the yard without stopping to ask permission to hunt or to even be on our land in the first place. We don't always see them go through, but find evidence of what happened later.

We also have a problem with wild animals walking through the yard.

Now, a simple motion detector in the driveway can alert us if either a deer or a vehicle goes past, but it can't distinguish one from the other. It might go off in the middle of the night and we see it's just a deer going past the driveway. We'd like it to go off if a vehicle goes through (night or day), but not when a deer goes past. In other words, wake us up if someone drives in the yard, but ignore the deer or other animals walking through.

I'd like to build something that sees the vehicle, ignores the deer, send a radio signal from the driveway to the house to sound an alarm and runs on a 9v battery for extended periods of time like the existing motion detector does.

All of this should be easy except the detection process. Any ideas on how the PIC could tell the difference and possible related hardware? Remember, for now I'm just toying wiht this idea.

Thanks.

Bart