Ultrasonic sensor to "see" through?

Hi

Here is what I want to build for my project.

There are two boxes (made up of forexample paper), one is empty and one contains lets say a quarter (coin) .
I want to be able to distinguish the box that is empty from the one that is not.

My logical thinking says to use a ultrasonic/sound detector, but my question is does the ultrasound penetrate the paperwall and reflect of the coin back through the paperwall to the detector, or does that not work?

I am thinking something like how the transdusers work in ultrasound imaging, I might be very of here, but very open to suggestions :slight_smile:

brainstorming ON

To detect a coin, it would be much easier to use a metal or conductivity detector.

Hi thanks for the answer.

Would be so kind to link me to such a detector, cant seem to find one. are they cheap?

Would be so kind to link me to such a detector, cant seem to find one. are they cheap?

If the coin is metal and electrically conductive, then it could act like a switch/button when across two electrical leads.

if the box is made from paper, you can use ultrasonic sensor to detect the coin, but you must change the library to make filters, to not deect the paper, but seems not logic, like what jremington said, use metal detector more easy :wink: