Well, I feel like a dork. I just noticed the "driveway alarm systems" post already on this page. I can't imagine how I missed it cause I look over the first couple pages ALL the time.
I guess we're stuck with this one now, too, so I'll just keep an eye on both of them.
Sorry.

Here ya go - we have the optex 1000 - works great!

http://homesecuritystore.com/autogen/annun.html?pid=/autogen/annun.html

My dogs!

If they are dozing, people sometimes make it to the door without them knowing. They have a real fit when that happens!

We have this Dakota Driveway Alarm. I turn it off at night, due to deer. Falling leaves, squirrels and birds can also set it off but not too often.

Here is a link that might be useful: Dakota Motion Alert 3000

My alarm - and falling leaves, deer, racoons, squirrels and birds can also set it off

Motion sensors can be such a pain, going off with every critter that passes by. I don't know if it could be wired to ring a remote, but what about those "hoses" on the pavement at gas stations to alert the attendant that a car has pulled in? (This Senior remembers when that would bring someone out to pump your gas and clean your windshield. LOL)

Thanks for the links, guys. Those don't look too bad.

Chisue, I was also wondering about something like a hose that the car would have to physically drive over to set it off. That way, I could put it right on the cattle guard. With a motion sensor, I'm sure our cattle would set it off whenever they're in that area.

Do you suppose a major oil company's PR department could help you find out where the gas stations buy theirs? For that matter, maybe your local station would have a source; they must break sometimes and have to be repaired.

If that's what you're interested in, check out gate websites. We're putting in an electronic gate - one of the options was the thing you run over to let cars out on the way out (opted not to purchase). They are installed under the driveway by cutting out a small strip and installing the part, then you cover up the area. I bet it can be attached to an alarm somehow.

We bought two different wireless driveway motion sensors. The first went off with birds flying nearby, branches waving, etc. The one we have now only goes off when an object like a car goes by. If I walk down the driveway, it does not set off the chime. Cars do every single time. We're happy with this second sensor.

Avoid motion sensors. Search for an alarm that is triggered by the metal of a vehicle; sensor is buried adjacent to the driveway up to 200 feet from house. Locate the chime in bedroom or hallway close to bedroom. Only disadvantage is that the alarm is also triggered by ground lightning strikes in vicinity. We love our system; great complement to the alarm system.

craftsman, what brand/model do you have now that you are happy with?

A system like grandlaker mentions would seem to be my choice - a 'magnet' under the pavement detecting metal objects is how traffic lights "see" you to know if someone is waiting at or approaching a light. Seems like something similar should be available for a residence.

WOW! Who knew there were so many possibilities! Isn't this forum just the BEST?

Our unit is from Smarthome (console with 200' cable and probe). I don't know anything about the wireless units. Do not bury under the drive but to the side and be sure to mark (or measure)where the probe is located for future reference if something happens. If you plan to add an irrigation system or you digging for landscape, you may want to buy 8' electrical conduit and place the cable inside the conduit. No need to glue; just buy the conduit that has beveled ends and put them together as you run the cable through it.

this one is good.

Here is a link that might be useful: can't beat the price!!!

The one skatiero mentions is the one I bought and put away because it chimed all the time.

The one we like is also wireless, and can be found at the link below.

Here is a link that might be useful: DesignTech Wireless Driveway monitor

Never knew there were so many options. Wish I'd thought about that years ago for my current house. Not sure we'll have a very long driveway at the new one so probably not worth it. However, if we do I like the idea of this one.

grandma, beautiful alarm! gorgeous!

I have three alarms of my own. I highly recommend this particular variety of alarm to the OP. The only downside is the high maintenance cost, but the benefits far outweigh the cost. My middle alarm has expanded since this picture was taken, but it was still effective even in miniature size: