PICKINI V4 - an easy to build, self adjusting PI detector

[SaltyDog]

I have started my thread here --> https://www.geotech1.com/forums/show...Metal-detector

[SaltyDog]

many thanks ....

Bernard, thanks for putting up with my modifications to your original design/thread, but it is time now to start my own thread, so will no longer clutter yours .. even if it is related ..

One last note in this thread:
I have a row of 5 LED's on my FPGA board and each LED is mapped to a metal type, works very well ... seems to give more information than purely tone.
I do have tone for target detection though, then just a glance down to see what metal it is ...

[Arionas]

... and here is a rough block-diagram of what I have implemented in the FPGA ..

[ATTACH]49851[/ATTACH]

.. oops sorry it is upside down

[SaltyDog]

What I think he means is which specific board, when you google it there lots of different prices and boards

AH, well I am doing development on the Lattice board, but I intend using the TinyFPGA BX board located here: https://github.com/tinyfpga/TinyFPGA-BX
The board is only $30

[6666]

Hi, as mentioned earlier, I am using an Lattice ICE40HX8K....so far have only used 35% of the 8k LUT's.

What I think he means is which specific board, when you google it there lots of different prices and boards

[SaltyDog]

which fpga do you work with?

Hi, as mentioned earlier, I am using an Lattice ICE40HX8K....so far have only used 35% of the 8k LUT's.

[useus]

... and here is a rough block-diagram of what I have implemented in the FPGA ..

[ATTACH]49851[/ATTACH]

.. oops sorry it is upside down

which fpga do you work with?

[dbanner]

It is very nice to have a block diagram of the circuit.

[SaltyDog]

... and here is a rough block-diagram of what I have implemented in the FPGA ..



.. oops sorry it is upside down

[SaltyDog]

Further update:

I have managed to extract a metal Id number for each metal type.

Gold and silver and stainless steel come under one Id,
Iron is another,
Lead is another

I haven't tried any other metals just yet ..

I will be mapping these to tones for in the field, as I want minimum controls, I envisage only a threshold adjustment, and maybe a pin-point button..

Cheers

[SaltyDog]

Well done satlydog.

This is my machine which detects only gold and ignores all other metals. Notice the dual slopes on either side of the centre sample point which is curved at the top. I am looking to apply for a patent for my device, though it suspiciously resembles but not to be mistaken with another device which is in common everyday use. This is entirely different beast.

A little humor to break the monotony of the quarantine, spirits are sagging over here.

Hehehehehe .... Hahahahahah ...

[MartyJ1963]

@SaltyDog,,,,,Well done! I've been following this thread since it began in 2016 and Bernard's Pickini is near the top of the list as one of my favourite Homemade PCB's,,,looking forward to seeing forth coming results with your experiments,,,Good luck,,, eagerly awaiting! Regards, Marty

[dbanner]

Well done satlydog.

This is my machine which detects only gold and ignores all other metals. Notice the dual slopes on either side of the centre sample point which is curved at the top. I am looking to apply for a patent for my device, though it suspiciously resembles but not to be mistaken with another device which is in common everyday use. This is entirely different beast.

A little humor to break the monotony of the quarantine, spirits are sagging over here.

[6666]

Well done

[SaltyDog]

UPDATE my friends ..

I have managed to detect my gold wedding band (worn very thin) at 200mm AND discriminate that it is gold. (All on a fairly standard coil)
I can now if I want, eliminate everything except gold .. AND still detect it at depth, which I could not do yesterday .. yahoo ...

I have managed this with judicious use of technology including FIR and IIR filters, and dual detection slopes ..
(one for sensitivity and one for discrimination)

I am still using the MPP board for this ... only connection is the pre-amp output (it is a dual pre-amp design) ignoring the rest of the circuit, and also using a Lattice ICE40HX8k FPGA.
I havn't even got offset control at the moment, that could make it even better in the field ..

All in all an excellent day ...

Bernard .. thank you for your excellent idea's, but I think I have crashed your thread enough, time to start my own, as this is a quite different beast now.