Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[wtrk]

Hi ... the detector is a pulse induction detector which are generally more resistant to mineralisation. This detector uses some ideas to increase the sensitivity to smaller targets and also to reduce noise.

It is mainly designed for conditions in Australia ( and may suit other places ) where there is a high degree of mineralisation in the ground but relatively little trash ( compared to Europe ).
The main target of interest in Australia is gold nuggets which forces the detector designers to detect smaller nuggets or deeper nuggets.

By using active damping the target sampling can be done earlier and if you are aware of how a pulse induction detector works then you can detect smaller metallic objects.
Noise reduction is also important particularly near power lines. I think this detector will work OK on the beach also .... I didnt find any gold during testing but did find alot of junk in a very short time.

moodz

Brother Im living Türkiye and here there are lot of black mineralization rocks and stones especially near volcanic area. There is no power lines because these areas are far from living area and people left there. But almost all of the pi detectors gets beep beep beep voice. Thats way I have asked about the mineralization.

[eclipse]

I really wished you'd picked NMOS like the previous design. This circuit would be awesome if it could be coupled with bipolar designs

[moodz]

Hi Moodz,
Just curiours, which LCD and rotary encoder did you use, or were you considering to use..?

Alps rotary encoder and 2004A generic 4 line LCD with serial / par module ( see ebay or alibaba ).

See the source code for references.

I have not finalised the menus ( keep changing my mind ) but if you attache the rotary you get volume control.

moodz

[moodz]

I really wished you'd picked NMOS like the previous design. This circuit would be awesome if it could be coupled with bipolar designs

Your right ... The V3 is very sensitive but NMOS or SIC will allow more power to the TX without sacrificing damping speed. Working on a plan now.

moodz

[Dean Sarelius]

Alps rotary encoder and 2004A generic 4 line LCD with serial / par module ( see ebay or alibaba ).

See the source code for references.

I have not finalised the menus ( keep changing my mind ) but if you attache the rotary you get volume control.

moodz

Hi Moodz,
Just been reviewing your source code it is very neat and easy to read, I am sure you have written code once before right...just kidding.
Have a few questions re main.c
Q1 - PIN 25 = Not Used = 400kHz pwr sync clock << I gather there was no need to use the power sync option on pin25..?
Q2 - OpenTimer3 comments refer to OpenTimer5 but gather that these comments are applicable to Timer3 is that correct..?
Q3 - INT16 initialize() refers to PIC32MX250_setup_pins() but gather that both the 150 and the 250 are identical in their pin out so no problem to leave as is..?

FYI - I am planning to layout a 4 layer SMD version of your design and will make it available to the rest of the forum when completed.

Before I do however would prefer to base it on what you consider to be a final revision so will remain on standby.

Cheers

[moodz]

Hi Moodz,
Just been reviewing your source code it is very neat and easy to read, I am sure you have written code once before right...just kidding.
Have a few questions re main.c
Q1 - PIN 25 = Not Used = 400kHz pwr sync clock << I gather there was no need to use the power sync option on pin25..?
No power sync need for liner regs :-) .... however i have another version that uses a switchmode and then it is.
Q2 - OpenTimer3 comments refer to OpenTimer5 but gather that these comments are applicable to Timer3 is that correct..?
Yes .. I think I changed timers at one stage and maybe comments dont match now ... correct. ( i think )
Q3 - INT16 initialize() refers to PIC32MX250_setup_pins() but gather that both the 150 and the 250 are identical in their pin out so no problem to leave as is..?
same except for USB functionality. ( none on 150 )

FYI - I am planning to layout a 4 layer SMD version of your design and will make it available to the rest of the forum when completed.

Before I do however would prefer to base it on what you consider to be a final revision so will remain on standby.
not planning to change anything on the layout ... only the internal code dealing with serial / LCD / rotary ... so no schematic changes.
the only hardware change might be bring out the pins I didnt use on the CPU to the headers .. no biggie.

Cheers

[Dean Sarelius]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

[eclipse]

As for the SIC look for UnitedSIC devices. They are driven by regular mosfet voltages and provide drop in upgrade /low Coss, low Rds, etc/

[waltr]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

I do recommend running traces from ALL unused PIC32 pins to a header or at least to thru-hole pads. This allows easy modification and/or adding/chaning a feature using another pin.

[pustareka]

moodz
Minelab crasher ?

[KingJL]

Paul, thank you for your answers... the rearranged diodes a great change. I think I will layout a compact pin pointer. is a great

First iteration of a miniature MAGPI v3 in SMD. Board is 100 mm x 50 mm.

[Mdtoday]

Great work James!

[moodz]

First iteration of a miniature MAGPI v3 in SMD. Board is 100 mm x 50 mm.

Really excellent work ... one thing I might mention is that the filter for the balanced PWM audio is a simple RC low pass. ( x 2 ) ... though a single leg can be used to ground with a DC blocking cap ( non polarised ) of suitable value.
If an RL low pass is used then considerably more audio power will be delivered. ( ie louder ) I have used a 5.6 mH inductor with 10uF cap or 1 uF cap for higher freq response for 32 ohm headphones.
Might be worth allowing for the inductor or resistor option in the filters .... the inductor packages will generally take up a bit more space than a resistor.

moodz

[moodz]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

For NMOS
The biasing is setup for grounded coil and +positive TX supply ( ie PMOS ).
NMOS would require a negative TX voltage for grounded coil.
Supplies to the preamp loops would need changing.
Various diodes would need reversing.
The voltage mutliplier would need to be pos instead of neg.

If that was done then no problemo.

short answer .. prob save it for V4
moodz

[wtrk]

Dear moodz now is it possible to make it ? I want to make it but if it is not ready I want to wait more for pcb order, what do you think about pcb changes future ?