user27246: please I'm aiming to do a project for parking system but first of thing I need a sensor to detect there is a car or not other than ultrasonic sensor ..
please any one know any kind of those sensors ? pressure sensor or normal sensor ? 

user27157: Ideas and concepts you could use:
1 - Laser tripwire - acts like a laser security system. If the beam is broken, then you car is there. Put a laser on one side of your garage and a photocell and the other and read its value.
2 - photocell under the car - if the area is always lit, you might be able to put a photocell below the parking spot. Then when your car is on the photocell, it return a different value then when there is nothing.
3 - pressure/weight sensor - both will detect the presence of a heavy object on them.
Hope those ideas hepled you!

27246: <p>please I'm aiming to do a project for parking system but first of thing I need a sensor to detect there is a car or not other than ultrasonic sensor ..</p>

<p>please any one know any kind of those sensors ? pressure sensor or normal sensor ? </p>
 27157: <p>Ideas and concepts you could use:</p>

<p>1 - Laser tripwire - acts like a laser security system. If the beam is broken, then you car is there. Put a laser on one side of your garage and a photocell and the other and read its value.</p>

<p>2 - photocell under the car - if the area is always lit, you might be able to put a photocell below the parking spot. Then when your car is on the photocell, it return a different value then when there is nothing.</p>

<p>3 - pressure/weight sensor - both will detect the presence of a heavy object on them.</p>

<p>Hope those ideas hepled you!</p>
