Over on GitHub user eldraco has uploaded an RTL-SDR compatible python script for detecting and locating eavesdropping spy microphones (bugs) within a closed environment. The Python script can be run either on Linux or Windows. They write:
Salamandra is a tool to detect and locate spy microphones in closed environments. It find microphones based on the strength of the signal sent by the microphone and the amount of noise and overlapped frequencies. Based on the generated noise it can estimate how close or far away you are from the mic.
Salamandra can either be used in live mode, or can use data recorded from rtl_power. It seems that the software simply attempts to detect peaks in the spectrum that look like analog audio, and print out their frequencies.
We’ve also seen this somewhat related piece of software called rtlsdr-wwb-scanner which can be used with an RTL-SDR to scan for microphones as well. However, this software is mostly intended to be used with the Shure Wireless Workbench which is a professional program for managing multiple microphones used in conferences, theatre performance, concerts etc.
In a previous post we also showed rtlmic, which is a program that can be used for receiving microphones and outputting audio to JACK.