A Question about ultrasonic range meters

Have several sensors spaced 90cm apart, with a float switch on each so you can determine which sensors are not presently covered by liquid.

I guess the range depends on whether the signal can travel in a tube or whether is is in the open.

Rene

Hello Sara,

Both. Resolution goes up with frequency but your electronics must be up to snuff, especially if you want to extricate phase angles. Most likely you have to become very familiar with I/Q mixing and detection. Analog Devices and Mini-Circuits carry the relevant parts for that.

Why was the range limited? What's the liquid? How do you focus the beam?

Anyway, before you get too carried away with achievable resolution look at the fluid to be measured. I'd bet that it's ultrasonic properties will not be constant over pressure, temperature etc. Look closely at the sound velocity in it and how it changes with other parameters. This data isn't always published but can be measured.

Then there is a whole other topic to ponder: Gas micro bubbles in the liquid. These will scatter the ultrasound signal no matter how good you focus the beam and influence the velocity of sound.

The liquid in the tank is petrol or gasoline and the minimum range is

I'm measuring the level of liquid through the air(the space above the liquid).I want ot know if it is possible to gain 1mm resolution with

The name of article is "Extending the accuracy of ultrasonic level meter" at : stacks.iop.org/MST/13/598 by P.Olmos.And also i found another article that is "Fast processing techniques for accurate ultrasonic range measurments"By B.Barshan which explained four methods for measuring TOF one of them is sliding-window which is exactly the thing I'm looking for.I will still appreciate more information or circuit for the method. Thanks a lot S.Azimi