Woah. A bit of reading shows that the signal would be incredibly weak, especially because of shielding. I wonder what other ways there might be to detect it.

Woah. A bit of reading shows that the signal would be incredibly weak, especially because of shielding. I wonder what other ways there might be to detect it. Someone else mentioned literal vibration, but I figure a contact mic would already pick that up – I mean, sound is already vibration...