I want to be able to sense the presence of a vehicle in a parking space. What type of sensor could I use to do so that wouldn't require invasive (digging asphalt) installation?

This must be a low-power solution. I've thought about using a photoelectric sensor, but I don't think that's a good idea as it would detect ANY object and not just a vehicle.

  • \$\begingroup\$ you have to use some image processing system if you want to detect cars,sensors are not designed to detect cars :) \$\endgroup\$
    – Lokanath
    Commented Sep 2, 2015 at 6:44
  • \$\begingroup\$ Is this for a specific parking space or just in general? If the former, indoor or outdoor? If outdoor, does either side or front butt up against a wall so a sensor could be placed there? \$\endgroup\$
    – tcrosley
    Commented Sep 2, 2015 at 9:21
  • \$\begingroup\$ Maybe just use an RFID tag; and just make sure you don't run over the reader. \$\endgroup\$ Commented Sep 2, 2015 at 12:02
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    \$\begingroup\$ @User12345 Don't rewrite the question to the point where the answer (accepted by you) no longer makes sense. If you have a new questions, then post a new question. \$\endgroup\$ Commented Oct 11, 2015 at 3:13
  • \$\begingroup\$ You could use some IR leds and a phototransistor to detect the beam emitted by the led. \$\endgroup\$ Commented Oct 11, 2015 at 3:32

2 Answers 2


If you want to create an inductive sensor without hurting your asphalt then try making a loop using thin metallic sticky tape. If you need to make cross over loops of metallic tape use a non-metallic tape to bridge the cross over points. Then over-coat the whole area with a thick durable paint if you need it to last.

To reduce total power usage energize the loop only at a very low duty cycle, (maybe only 1 second per minute). If there are several parking spaces you might multiplex each location for the short duty cycle time as a counter increments. With that method you can not only count the total cars but also record exactly which spaces are occupied.


Parking garage sensors use ultrasonic distance measurement to check for something that is closer than the floor or IR reflection as far as I have deduced from the look of the roof mounted sensors. I suppose micro power impulse radar or a inductive metal detector system could also be used.

Much depends on how cheap and how accurate you need the sensing to be.

A camera and some clever software is a practical option but will be expensive if you have lots of parking bays.

An optical mouse camera may be the cheapest novel option for large numbers and can measure the speed of the car entering the bay if it is located above the parking bay. Some can be configured to output the 16x16 pixel image in debug modes. Remember you heard about it on electronics stack exchange first :-)

If you can put a bar-code on the roof of the car you could scan then as they drive into the yard or parking bay to make sure it it the right car. Use IR absorbing strips on the roof and they will not be very visible.

Image recognition on a numberplate could work, you need to take a photo every 30 seconds and see if there is a valid plate.

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    \$\begingroup\$ Our local supermarket has a sensor above each parking space so it can detect cars that have been parked for more than 3 hours. It seems to be a metal detector of some kind. \$\endgroup\$ Commented Sep 2, 2015 at 7:57

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