Carl MFD article ,5KHZ frequency ?

[Esteban]

Hi J_Player,

You emit a IR-laser or IR modulated in audio beam, NO A FIX BEAM in wich you insert the tone via a capacitor. No, you ON and OFF the IR diode at this tone frequency, can be 400 Hz. This tone (modulation) appears as a phase shift in a receiver system. I only try with IR, but sure IR-laser will be better, but much more expensive in comparation. Not for to measure temp, but this beam is like a precisse antenna in wich beam "travel" the phenomenom (because I try it only for old buried items, no for new) and dislocates the system. Also all bodies emit IR, metals in major quantity. But the question is: why I can't detect a person (wich emit IR) but yes a metal buried? What is the associated phenomenom inherent to this? Atomic vibration also? Is very complex!