Beat Balance Metal Detector


Posted on Nov 20, 2012

Various embodiments of the BB metal detector have been published, and it has been widely described in the press as a new genre. Instead of using a search and a reference oscillator as with BFO, or Tx and Rx coils as with IB, it uses two transmitters or search oscillators with IB-style coil overlap. The frequencies of the two oscillators are then mixed in similar fashion to BFO, to produce an audible heterodyne.


Beat Balance Metal Detector
Click here to download the full size of the above Circuit.

On the surface of it, this design would seem to represent little more than a twinned BFO metal detector. However, what makes it different above all else, and significantly increases its range, is that each coil modifies the frequency of the adjacent oscillator through mutual coupling. This introduces the "balance" that is present in an IB metal detector, and boosts sensitivity well beyond that of BFO. Since the concept borrows from both BFO and IB, I have given a nod to each of these by naming it a Beat Balance Metal Detector, or BB for short. Happy hunting!




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Pierce crystal oscillator
555 boost converter
IR Headset Circuit with headphone Transmitter and Receiver diagram
GPS-Disciplined 10 MHz Frequency Standard / GPS-Based Universal Time Clock
Ultrasonic sensors apply to parking sensor system
Short-Range Sonar with the BS2!
Projects
OPA606 capacitive load isolation buffer
Structure and working principles of various protective circuit diagram e



Top