My design and its depressing resoults

[Olly]

For TGSL... tough! Bad luck!
Tesoro coils from older series are simply "awkward" for finding the stock replacement.
I have no clue, honestly speaking.
Coil for Fisher Gold Bug Pro is what I used several times.
Inuctances and resistances are just sweet for adapting in diys.
But unfortunatelly not for Tesoro based diys.



P.S.
Coil for Fisher Gold Bug Pro:
TX = 0.87mH, 0.846mH, 0.85mH...... 33 to 42 ohms
RX = 8.7mH, 8.12mH, 8.61mH, 9mH... 1.8 to 2.9ohms

Thanks for your feedback, I'll experiment a bit with the Fisher type coils...

[Pep_T]

So, big news. The university where I work granted me some founds to buy some components for my project, we are talking about a couple hundred euros, no big deal, but I wanted to ask everybody WHAT do you suggest me to buy in terms of:

- OP-AMPS: TL07X series came to my mind, do you know of anything better?
- TX Drivers: I thought about LM386 and some mosfets for low side driving or H-bridge (I do not think I need mosfet driver too)
- Comparators;
- DSP: I am going for the dsPIC33 series
- Anything that comes to your mind.

I feel I have to explain that this word is for academic research only, other than my personal interest, but still I want to achive the best resoults possible. You have no idea of how many people told me "why don't you just buy one?". Really annoying.

[kt315]

tell to your professor you must build PI detector with discrimination of gold nuggets. it will have color LCD and free HEX/CODE for all members.
i hope the PHD will leave out the cathedra and with you you both will trip on the hunting...

[Carl-NC]

but I wanted to ask everybody WHAT do you suggest me to buy in terms of:

What do you plan to build?

[Pep_T]

Hi, I want to design an IB metal detector with multi frequency (start with just one frequency) capabilities and digital signal processing. The main goals are detecting a 2€ coin at some 40/50 cm and accurate discrimination. Once I have that working I will move on to a SuperD coil and try to use the double Ds as two eyes: I want to exploit the stereographic nature of the coils to allow very precise real time targeting of the object and maybe (HUGE maybe here) perform some signal processing in order to predict dimension, shape and other charapteristic of the target.

All of my work will of course be based on a Digital Signal Processor but some analog for the coils front end is clearely needed.

I know this sounds like a lot, I am aware that will require a lot of work. I want then use the project as my master degree thesis and who knows what happends later!

PS: I never experimented with soil effects but that will be something that I will face later. For now all tests are in air

[ivconic]

Hi, I want to design an IB metal detector with multi frequency (start with just one frequency) capabilities and digital signal processing. The main goals are detecting a 2€ coin at some 40/50 cm and accurate discrimination. Once I have that working I will move on to a SuperD coil and try to use the double Ds as two eyes: I want to exploit the stereographic nature of the coils to allow very precise real time targeting of the object and maybe (HUGE maybe here) perform some signal processing in order to predict dimension, shape and other charapteristic of the target.

All of my work will of course be based on a Digital Signal Processor but some analog for the coils front end is clearely needed.

I know this sounds like a lot, I am aware that will require a lot of work. I want then use the project as my master degree thesis and who knows what happends later!

High demands!

[Pep_T]

Well, of course that would be the best case scenario, I would settle for less

[Riss]

Hi, I want to design an IB metal detector with multi frequency (start with just one frequency) capabilities and digital signal processing. The main goals are detecting a 2€ coin at some 40/50 cm and accurate discrimination. Once I have that working I will move on to a SuperD coil and try to use the double Ds as two eyes: I want to exploit the stereographic nature of the coils to allow very precise real time targeting of the object and maybe (HUGE maybe here) perform some signal processing in order to predict dimension, shape and other charapteristic of the target.

All of my work will of course be based on a Digital Signal Processor but some analog for the coils front end is clearely needed.

I know this sounds like a lot, I am aware that will require a lot of work. I want then use the project as my master degree thesis and who knows what happends later!

PS: I never experimented with soil effects but that will be something that I will face later. For now all tests are in air

Get some metal detector in your hands and get some practice in different terrains - beach search, abandoned vineyards - with lots of wires...in city parks, in the forest. at least 14 days (at least 80 hours) of practice. don't think about anything. don't work on metal detectors while gaining practical experience. your point of view will change radically. and you will never write such things again.practice is a great teacher and shows the right path ( way )

[Carl-NC]

Hi, I want to design an IB metal detector with multi frequency (start with just one frequency) capabilities and digital signal processing. The main goals are detecting a 2€ coin at some 40/50 cm and accurate discrimination. Once I have that working I will move on to a SuperD coil and try to use the double Ds as two eyes: I want to exploit the stereographic nature of the coils to allow very precise real time targeting of the object and maybe (HUGE maybe here) perform some signal processing in order to predict dimension, shape and other charapteristic of the target.

For the purpose of ordering parts, you need to figure out exactly what you want to build. That is, you need a schematic. Even if you plan to do a bunch of experimenting, you need a starting point.

[Orbit]

So, big news. The university where I work granted me some founds to buy some components for my project, we are talking about a couple hundred euros, no big deal, but I wanted to ask everybody WHAT do you suggest me to buy in terms of:

- OP-AMPS: TL07X series came to my mind, do you know of anything better?
- TX Drivers: I thought about LM386 and some mosfets for low side driving or H-bridge (I do not think I need mosfet driver too)
- Comparators;
- DSP: I am going for the dsPIC33 series
- Anything that comes to your mind.

I feel I have to explain that this word is for academic research only, other than my personal interest, but still I want to achive the best resoults possible. You have no idea of how many people told me "why don't you just buy one?". Really annoying.

I assume that someone gave you an idea? I'm thinking of setting up a project with full code for the new year with colorful colors, But only avr based on athmega 32p.Or maybe atmega328p I'll see.

[Pep_T]

For the purpose of ordering parts, you need to figure out exactly what you want to build. That is, you need a schematic. Even if you plan to do a bunch of experimenting, you need a starting point.

The design in my mind is pretty simple, see picture attached. All processing and detecting is done in software. I plan to perform an FFT on the received signal in order to extract as much information as possible from the received signal.

That's the reason I cannot just use an ATMEGA328P but I need something more powerfull, line an STM32F405 or better a dsPIC33. First because of the DSP capabilities of this devices, that allows me to perform the FFT at a much more efficient way, then for the provided ADC that will need to sample the signal at at least 100kHz, even tho I plan to use frequencies up to 25kHz.
The parts suggestions I was aiming to was particularely about the RX amplifier. In various schematics I sow the LM833, that does not look that bad, but it is a relatively old op amp and maybe I can try for something better. I surely didn't want a full shopping list

The driving circuit will probably be a PWM driven H-bridge, less likely to be a single switching low side mosfet.

[Orbit]

[КУОТЕ=Пеп_Т;н416706]

Дизајн по мом мишљењу је прилично једноставан, погледајте слику у прилогу. Сва обрада и детекција се обављају у софтверу. Планирам да извршим ФФТ на примљеном сигналу како бих извукао што више информација из примљеног сигнала.

То је разлог зашто не могу само да користим АТМЕГА328П, али ми треба нешто моћније, линија СТМ32Ф405 или боље дсПИЦ33. Прво због ДСП могућности ових уређаја, што ми омогућава да изведем ФФТ на много ефикаснији начин, затим за обезбеђени АДЦ који ће морати да узоркује сигнал на најмање 100 кХз, иако планирам да користим фреквенције до 25кХз.
Предлози за делове које сам имао за циљ односили су се посебно на РКС појачало. У разним шемама сејем ЛМ833, то не изгледа тако лоше, али је релативно старо операцијско појачало и можда могу да покушам нешто боље. Сигурно нисам желео пуну листу за куповину

Покретачки круг ће вероватно бити Х-мост вођен ПВМ-ом, а мање је вероватно да ће то бити једноструки мосфет са ниским преклопом.[/КУОТЕYou are indeed well on your way to prison. Stealing from other people's computers, intrusion into e-mail is cybercrime, have you really not understood that?

[Pep_T]

tell to your professor you must build PI detector with discrimination of gold nuggets. it will have color LCD and free HEX/CODE for all members.
i hope the PHD will leave out the cathedra and with you you both will trip on the hunting...

Of course I will. Once the project is complete it will be freely available. Besides, I hope you will follow the developement.

[Pep_T]

You are indeed well on your way to prison. Stealing from other people's computers, intrusion into e-mail is cybercrime, have you really not understood that?

And why would that be? Why are you making this assumptions?

[pito]

The driving circuit will probably be a PWM driven H-bridge, less likely to be a single switching low side mosfet.

STM32f102, PAM8610 ,TC4422, OP27, MCP6022.

Start with FFT phase detector, if you manage that = 50% job done.