Idea for an add on for pi detector

[wyndham]

Now since the folks here have an insight into what works and what won't, I suggest an add on to a PI. It's up to those here to see if it has merit or not.
I'm wondering if a smart phone or Pad might have enough CPU speed and program-ability to take the signal(Somewhere along the signal Path) from a PI and further process this signal and disply it on the smart phone/Ipad/Android screen that will give more complete information about the signal than just a noise in the headphone. At the lest, you could see a signal before the threshold of sound starts. For us that are hard of hearing, this would help a great deal. My hearing loss is about 30-40%
Just a thought since the CPU power in these units have increased several fold in the last few years.
Let me know what you think. Wyndham

[Carl-NC]

They probably have more than enough horsepower, most are using hotrod ARM processors. Probably don't have a good enough ADC, though.

[mario]

can't provide you links but I know there are open source projects out there begun for turning android phones into oscilloscopes

[wyndham]

Carl, would a fast 16 bit ADC that takes the RX signal from the coil and sends the digital to a software analysis package that outputs to a screen have any advantages over what a P I gives now? If so I saw several eval boards from Analog Devices that input the signal and out puts 16 bit.
Here's a link
http://www.analog.com/en/analog-to-d...C_a/press.html
Your the bit pusher
Just wondering, Wyndham

[Carl-NC]

One of my projects is an R&D PI using direct sampling with an 18-bit ADI Pulsar ADC. My experience is that sampling a traditional PI decay curve does not offer much benefit for advanced analysis. So we are looking at significantly different PI waveforms. I can't really divulge what they are, but one is easy to guess.

[mikebg]

My experience is that sampling a traditional PI decay curve does not offer much benefit for advanced analysis. So we are looking at significantly different PI waveforms. I can't really divulge what they are, but one is easy to guess.

Here's a suggestion for most suitable waveform - the sinc function. It is described in November 08, 2001 08:38PM by Carl Moreland under the name "sine(x)/x looking waveform":
http://www.findmall.com/read.php?34,129198
Here you can see the sinc pulse in time domain and its spectrum in FD:
http://www.geotech1.com/forums/showp...5&postcount=24

[moodz]

Here's a suggestion for most suitable waveform - the sinc function. It is described in November 08, 2001 08:38PM by Carl Moreland under the name "sine(x)/x looking waveform":
http://www.findmall.com/read.php?34,129198
Here you can see the sinc pulse in time domain and its spectrum in FD:
http://www.geotech1.com/forums/showp...5&postcount=24

Carl can have credit for thinking of it .... but I actually did it

see http://www.geotech1.com/forums/showp...8&postcount=42

There is also phase magnitude plots in that thread also.

Realised on both DSP and soundcard / laptop.

DSP is more accurate / timing. Laptop is easier development.

Since I am working on monocoil type Pi projects at moment this one is a backburner because I would still need a balanced coil ... but the code and hardware is sitting there ...


Regards,

moodz.

[Aziz]

Hi all,

the netbook + soundcard solution works really fine. It's cheap, has enough horse power (more then you really need), it uses continious wave (CW) sampling and performing DSP on it.

Response signals up to 48 kHz bandwidth can be sampled and processed in real-time. This is really enough for a good working detector.

You also need not to develop a µC/DSP platform. You can use the conventional C/C++ compilers, soundcard drivers, ... it's an unique fast development and analysing platform (R&D). I personally prefer Windows XP as O/S. Forget all the other platforms. Take the simplest, well proven and open one.

Now fasten your seat belt before taking off:
You can make it working to be "Worlds best ground balancing and discriminating metal detector!".
No more hot rock detection, works on highly mineralized ground, no ground balancing problems, etc...

You can use any coil current wave form. You just need to synchronize the detector controller box with the processing software. This can be done via the soundcard output line.

Cheers,
Aziz

[WM6]

Now fasten your seat belt before taking off:
You can make it working to be "Worlds best ground balancing and discriminating metal detector!".
No more hot rock detection, works on highly mineralized ground, no ground balancing problems, etc...

You can use any coil current wave form. You just need to synchronize the detector controller box with the processing software. This can be done via the soundcard output line.

Cheers,
Aziz

Excellent news Aziz.

My seat belt refuse to fasten it, saying: "Not again?"

[moodz]

Hi all,

the netbook + soundcard solution works really fine. It's cheap, has enough horse power (more then you really need), it uses continious wave (CW) sampling and performing DSP on it.

Response signals up to 48 kHz bandwidth can be sampled and processed in real-time. This is really enough for a good working detector.

You also need not to develop a µC/DSP platform. You can use the conventional C/C++ compilers, soundcard drivers, ... it's an unique fast development and analysing platform (R&D). I personally prefer Windows XP as O/S. Forget all the other platforms. Take the simplest, well proven and open one.

Now fasten your seat belt before taking off:
You can make it working to be "Worlds best ground balancing and discriminating metal detector!".
No more hot rock detection, works on highly mineralized ground, no ground balancing problems, etc...

You can use any coil current wave form. You just need to synchronize the detector controller box with the processing software. This can be done via the soundcard output line.

Cheers,
Aziz

??? Windows is not open , simple or proven ???
GCC compiler for Linux is far and away better on Linux and I get 192 khz sampling on most sound cards .... leaves Windows in the dust plus you can strip down bootable system to fit on much less than 10 MEG flash including graphics and all dsp code. I will be swinging my coil while your xp is still booting LOL.
Cheers from moodz.

[moodz]

Now since the folks here have an insight into what works and what won't, I suggest an add on to a PI. It's up to those here to see if it has merit or not.
I'm wondering if a smart phone or Pad might have enough CPU speed and program-ability to take the signal(Somewhere along the signal Path) from a PI and further process this signal and disply it on the smart phone/Ipad/Android screen that will give more complete information about the signal than just a noise in the headphone. At the lest, you could see a signal before the threshold of sound starts. For us that are hard of hearing, this would help a great deal. My hearing loss is about 30-40%
Just a thought since the CPU power in these units have increased several fold in the last few years.
Let me know what you think. Wyndham

I reckon staring at a visual indicator would be somewhat tiresome and maybe dangerous in some situations. I reckon a better approach would be to include a vibration unit in the detector handle you would then use your hand as your "ear". By varying the frequency of the vibration and maybe pulsing it on and off Target infos can ne sent to the user.
Moodz

[Aziz]

??? Windows is not open , simple or proven ???
GCC compiler for Linux is far and away better on Linux and I get 192 khz sampling on most sound cards .... leaves Windows in the dust plus you can strip down bootable system to fit on much less than 10 MEG flash including graphics and all dsp code. I will be swinging my coil while your xp is still booting LOL.
Cheers from moodz.

Hi moodz,

why not Linux. It needs by far less flash ROM indeed. You can mount your HD out of the netbook and save a lot of power. A flash memory card should do this well. I even haven't installed a HD in my netbook (flash card installed).

Good to know, that Linux soundcard drivers support 192 kHz now.
I know, that some soundcards support this for XP too.

Well, one can configure XP with less installed services and make it lighter and faster.
It's only a question of "taste" or "computer religion" of course.

Cheers,
Aziz

PS: Have a look at the new Tablet PC's!!! It's going to be interesting now.

[moodz]

Hi moodz,

why not Linux. It needs by far less flash ROM indeed. You can mount your HD out of the netbook and save a lot of power. A flash memory card should do this well. I even haven't installed a HD in my netbook (flash card installed).

Good to know, that Linux soundcard drivers support 192 kHz now.
I know, that some soundcards support this for XP too.

Well, one can configure XP with less installed services and make it lighter and faster.
It's only a question of "taste" or "computer religion" of course.

Cheers,
Aziz

PS: Have a look at the new Tablet PC's!!! It's going to be interesting now.

he he just giving you friendly poke. Of course XP will do job but why pay money to Micro$oft

moodz

[mario]

With faster processors coming from Ti and/or Nvidia, it pays to think outside the box (
http://developer.android.com/guide/topics/usb/adk.html).

I think most of us are heading this way.

Hi moodz,

why not Linux. It needs by far less flash ROM indeed. You can mount your HD out of the netbook and save a lot of power. A flash memory card should do this well. I even haven't installed a HD in my netbook (flash card installed).

Good to know, that Linux soundcard drivers support 192 kHz now.
I know, that some soundcards support this for XP too.

Well, one can configure XP with less installed services and make it lighter and faster.
It's only a question of "taste" or "computer religion" of course.

Cheers,
Aziz

PS: Have a look at the new Tablet PC's!!! It's going to be interesting now.

[wyndham]

Hey there's a lot of stuff out there. Take a nap for a few months and the world changes. Now I'm also wondering if someone were to retro fit an older ML like a 2200 or other cheaper model with what we're talking about here, would the TX power punch down deep enough to give more info on the RX to be processed.
My first thought is to use the TX part of the older PI to get the power out and the sound card/dsp/android processes the signal to give more target information than what is available through the RX circuit out to headphones, true or not.
Wyndham