Back in 2018 we posted about someone who had combined an ultrasonic piezo speaker and an SDRPlay RSP1A in order to create a device that can detect the ultrasonic sonar sound from bats.

Recently on YouTube Matt from the TechMinds YouTube channel was able to create a similar system using a MEMS microphone from Knowles which can receive audio in the 100 Hz ~ 80 kHz range. He connects the microphone to a 3.3V supply and connects the output of the microphone to his SDRplay RSPDx.

The system was then able to successfully hear the sound of bat sonar at his home location in the UK.