Vehicle Sensor - how to design it?

[ASIC]

Vehicle Sensor

Hi,

I need to design a car sensor to be places in the ground under the road for detecting the precense of cars. The system must be static, i.e. I can power down the sensors, and when powered up again, I can check if there is a car there or not. Any design ideas?


ASIC

 

[ted]

I am not an expert in this stuff at all, but what I would do is to see variations of the conventional magnetics principles. One interesting article is http://www.itsa.org/subject.nsf/Files/3116/$file/3116.pdf


Good luck,
Ted

 

[mr_ghz]

Hi asic

I see two possibilities:
1) A car is made with a lot of metal. If you use a big inductor built under
the car and use this inductor to build an oscillator you can see a drastic
frequency-change if a car is placed above the inductor
2) You use a radar or ultrasonic distance-sensor. If no car is present, you
will see (perhaps) an object in a distance over 2 meters (your roof). If
a car is present, this distance goes down to about 0.4meters

Greets