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Vehicle presence detection using magnetic sensors

Alexandru Iordan
Prodigy 20 points
Other Parts Discussed in Thread: DRV425

Hello,

I am developing an on-ground sensor for car presence detection. It is powered-up by a better so it needs to be low-powered.

Would you please recommend the most appropriate magnetic sensor for this application?  

If there is any reference application available, that would be great!

Best regards,

Alex

  • 0
    TI__Mastermind 21720 points

    Hello Alex,

    Thanks for considering to use Texas Instruments.  Could you provide a little more information on what is providing the magnetic stimulus you intend to detect with our sensor?  Will you have our sensor in post in the ground that detects a magnetic field from a magnet in the bumper, or something else?  What is the average distance between your magnetic source and sensor you are hoping to design?  Are you wanting a linear response from the sensor or are you wanting a logic output?

  • 0 in reply to Patrick Simmons
    Prodigy 20 points

    Hi Pattrick,

    There are products on the market using magnetic sensors for car presence detection. I believe they are monitoring the earth's magnetic field deviations generated by the vehicle that parks above.

    So yes, the sensor will be on the ground, but there will be no magnet in the bumper, but only the car itself.

    I would say the range from the sensor to the bottom of the vehicle is between 15 and 40 cm.

    Related to the output, I would say logic, but if there is a linear response sensor that makes my life lot easier, I am interested.

    Alex

  • 0 in reply to Alexandru Iordan
    TI__Mastermind 21720 points

    Hello Alex,

    If you are monitoring deviations in the earth's magnetic field then you are measuring a very small magnetic signal.  It varies with location and the max you might expect without some special magnetic concentrator might be around 60uT.  As the signal is so small, a Hall-effect sensor might not be the best option.  For instance, with our DRV5055A1 with a sensitivity of 100mV/mt, that would equate to around 6mV and any small variations in that would likely be buried in the noise of the part.  You might want to consider a fluxgate sensor if you intend to proceed with magnetic sensing and do not plan on attaching anything to the car that might provide a stronger signal.  The DRV425 might be something to look into.