Mass Detection

I've played around for about 2 months with my Arduino and I'm loving it. For my next project I would like to configure Arduino to detect if a car is in the driveway. I'm not sure what kind of sensor I'm in need of.

Motion detection does not fit the bill, I simply want to know if a car is parked in a spot in the driveway.

Magnetic switch might work, but I'd rather not have any wires laying in the driveway, nor do i want to bury any sensors.

My plan is to mount Arduino kit inside the garage, wired up to a sensor on the outside.

I was hoping this group could point me towards some sort of sensor that could detect when an object is in a certain spot.

thanks in advance

Well that's a tough one. You want remote sensing but do not want wires.

Do you want to know if the car is there while it is sitting still or do you want to know when it comes and goes?

If the former you can use a laser, photo transistor and corner reflector but that will get fairly complicated. You would pulse the laser on then off at intervals to prevent burning it out. Once every minute or so should do ok.

If the latter look at a PIR sensor.

http://www.sparkfun.com/commerce/product_info.php?products_id=8630

"This is a simple to use motion sensor. Power it up and wait 1-2 seconds for the sensor to get a snapshot of the still room. If anything moves after that period, the 'alarm' pin will go low."

There should be a number of project using that, just search the forum for it. It will require mounting it within it's detection range but that can be on the side of a building near the parking spot.

Both have a disadvantage in that there is no way to discriminate what is causing the alarm.

If you take a look at GSpy and understand the code you could set up a webcam to look for somehing in that spot that matches a patter.

http://gspy.sourceforge.net/

I don't know how well that program will work but it's free

Check out this driveway alarm from Mighty Mule at Lowes:

http://www.lowes.com/pd_40595-60740-FM131_0_

?Detects vehicles entering or exiting your driveway and sends a wireless signal up to 400 feet to the indoor base station, activating a "door chime" announcement ?Electromagnetic sensor only senses large metal objects avoiding false signals due to animals or children. ?Easy-to-install and mounting stake is included in the kit ?Includes two keys and a keyed manual release