ultrasonic sensors

[stranger]

i am planning to use car revers parking sensors for sensing in robotics and i found out that there are two kinds of sensors

one kind have sensors with 3 pins.......which i guesses as vcc ground and signal.....


the other have two pins so i thought they act as variable resistors depending on distance.....

am i right?

 

[(*steve*)]

probably not

If you have part numbers for these parts then you could google for them and see what you get.

 

[ChosunOne]

Don't know if this helps you, stranger, but the alarm industry used to use lots of ultrasonic sensors decades ago, before they were supplanted by passive infrared sensors. I don't know how the car sensors work, but the ones in alarm systems measured relative velocity between source and target, and operated on doppler effect by comparing the frequency transmitted to the return freq of the echo.

Dunno if that helps, but I thought I'd toss it out just in case.

 

[stranger]

yeah.........thanks a lot.......