pi metal detector

[Mariusz]

How I can increase coil singnal in PI to achieve greater depth ? There's resistor which leads to coil is that's the way ?

[Carl]

Re: pi metal detector

>How I can increase coil singnal in PI to achieve greater depth ? There's resistor which leads to coil is that's the way ?


My guess is that you are looking at the damping resistor. Also, if you do manage to increase the coil signal you might also have to change the sample timing, not sure about this. Eric Foster's forum specializes in pulse induction, I'm just learning.


What detector do you have?


- Carl

• Eric Foster's PI forum

[Piotr]

Re: pi metal detector Proscan

>>How I can increase coil singnal in PI to achieve greater depth ? There's resistor which leads to coil is that's the way ?


>My guess is that you are looking at the damping resistor. Also, if you do manage to increase the coil signal you might also have to change the sample timing, not sure about this. Eric Foster's forum specializes in pulse induction, I'm just learning.


>What detector do you have?


Mariusz asked me the same question privately but I suspect he has "proscan-type" detector so I have decided to answer him on the forum.


There are two resistors that are connected to the coil. Neigther of them can increase coil current significantly. Carl is right they are mostly for dumping purpose.


The main problem with this design is PCB layout. If not designed properly, the crosstalks and noises spoil its performance and force to limit gain in preamplifier stage (that certainly influence the depth more than the coil current).


I have not tried to build the detector based on Paulo's PCB. I'd gladly hear from someone who did it.


Also, since the detector has no trimming elements for timing circuitry, the sample delay will not be set properly, I am affraid.


Piotr

[Mariusz]

Re: pi metal detector Proscan & Buccaro

>The main problem with this design is PCB layout. If not designed properly, the crosstalks and noises spoil its performance and force to limit gain in preamplifier stage (that certainly influence the depth more than the coil current).


So is there any way to improve PCB ? If not then I'll start building Buccaro, what do you think is it worth to try ?