The Great Search - Ultrasonic Transmitter/Receiver Element for Distance Sensing

We're interested in implementing an ultrasonic distance sensor on a microcontroller without using a 'standard' off-the-shelf chip with trigger/pulse mode. Also, because we're sorta curious how these things work! But first up we have to acquire some ultrasonic sensors. It's definitely easier to design a sonar with two elements - one to transmit and one to receive - but perhaps some clever code/hardware design could make it possible to do with one! Let's find a 40KHz ultrasonic transceiver we can get on Digi-Key to start our experimentations.See on Digi-Key https://www.digikey.com/short/v8h0wzt7