Denis Laskov’s “Eye on Cyber” pointer to a USENIX Security 2025 paper by Onishi et al. The research shows that MEMS microphones, because of their PDM (Pulse Density Modulation) digital interface, radiate unintended EM signals that still carry the original audio. With nothing more than copper-foil-tape antennas, the authors recovered enough signal through a 25 cm concrete wall at 2 m to hit 93% speaker-recognition accuracy — a TEMPEST-class result for cheap consumer mics. core-jmp.org/2026/05/mems-m…