What is the ping sensor?
https://www.parallax.com/product/28015I think the resolution of the Ping (and similar ultrasound sensors) is just under a centimeter. If I did the math right, the wavelength of sound at 40KHz is 8.5mm. I think the resolution of an ultrasound sensor is limited by the wavelength. Medical ultrasounds use much higher frequencies.I'm not sure is the wavelength really limits an ultrasound resolution. I've heard people I consider knowledgeable about this topic disagree with this claim.
Well no, ultrasound works on a delay between propagation and echo. This is dependent on the speed of sound in a medium...not its wavelength.