QUESTION FOR MR. FOSTER

[Anonymous]

I HAVE HAD ASSEMBLED A PI FROM A KIT. ALSO I HAVE SENEN THE PULSE STAR PI THAT INDICATES LOW CONDUCTIVITY LIKE RINGS ETC. AND SMALL IRON TARGETS AS "FEROUS"IN A GREEN LED, AND HIGH CONDUCTIVE AS "NON FEROUS" IN A RED LED, FROM WHAT STAGE OF THE CIRCUIT CAN I GET THAT INFORMATION AND HOW?

 

[Anonymous]

I am not sure of the specific arrangement used in the Pulstar, but it could be that they have an early sample and a late sample. Iron objects tend to have a signal that decays more slowly with time for a given size. The LED indicating ferrous would come on if these long decaying signals are sensed. Non-ferrous with shorter decays would light the other LED. This arrangement is not foolproof,as larger good conductors will also have a long decay and be misread. Likewise, very tiny iron objects may only exhibit a short decay.
To do this, you have to have a sample pulse generator that takes another set of samples at the receiver front end output and process it through another integrator and dc amplifier channel.
Eric.

 

[Anonymous]

THANK YOU MR. FOSTER,
IT WILL BE POSSIBLE TO CONNECT THAT SECOND SAMPLE PULSE GENERATOR, BUT IN NEEDS TO HAVE A LARGER SAMPLE WINDOW IN ORDER TO TAKE SAMPLES CAPABLE TO INDICATE A DIFFERENCE IN THE DC AMPLIFIER CHANNEL. IF IT IS TAKING SAMPLES BETWEEN 15us and 50us, I WILL END WITH A SIGNAL INTENSITY METER INSTEAD!...A RING DECAYS IN 50us, A NAIL MAYBE AT 300us, A SILVER COIN AT 400us, I MAY BE NEEDING A SAMPLE PULSE GENERATOR WITH A SAMPLE WINDOW BETWEEN 15us AND 600us, HOW CAN I DO THAT? DOES THE INTEGRATOR NEEDS MODIFICATIONS ALSO?
THANKS IN ADVANCE