TESORO GOLDEN SABRE

[Fred]

Hi Eugene,
The 7660 is a specialised circuit, it need few external components and works well, it´s like with the 7805 for voltage regulation but oher solutions are possible....:this one is said to deliver up to 40ma .

[ivconic]

Unfortunately you are up against some basic physics here. The way the Whites (or any other digital detector) displays "accurate" VDI numbers, is by having a lookup table in ROM of various phase angles measured for specific targets at various depths. By monitoring the amplitude and cross-referencing this with the lookup table, it is possible to "guess" the identity of the target. This is only really accurate when the target is relatively close to the coil, or when performed in an air test. The ground causes lots of distortion in the RX signal, which makes the target id inaccurate.
There is no easy way around this problem with an analog detector.

"..Unfortunately you are up against some basic physics here..."

Ha,ha,ha! I know that already, very good.
Don't tell ME that, tell that to ALL metal detector manufacturers as remark on their wild advertisments!
When i said "..smart done.." - i reffered that to smart White's strategy to elegantly solve disc inaccuracy above some depth limits. Good done - audio is further produced, BUT VDI do not respond above some limits. So operater is not fooled with their detector, as with majority of other models from other manufacturers.
I hope this is now more understandable?

Reffering this issue at "analogue" detectors...yes, i do seriously think there is certain way to overcome it. But i will not discuss that now. Time will come and we will discuss it in future.
Do not plead on some " basic physics.." here. Problem is tied up on more than just "basic...". Also "basic physics.." turned to be disproved by real practice many times so far. But we better do not discss this more here.
Regards!

[Qiaozhi]

Also "basic physics.." turned to be disproved by real practice many times so far.

For example???

[Fred]

For example???

Scientists lack imagination *

Fred.

* free provocation....muuahaha!!!.

[Qiaozhi]

Scientists lack imagination *

Fred.

* free provocation....muuahaha!!!.

Not that sort of example!

But to answer your provocation ... in reality I think it's quite the reverse. Scientists have too much imagination. Parallel universes, quantum teleportation, worm holes, time travel, to mention a few.
However, we are now going off topic. There's some danger of getting caught in the dark side.

[ivconic]

"..But we better do not discuss this more here.."

[simonbaker]

I think that is a Great Idea , and also run audio on a separate supply voltage . Speaking of voltage , can anyone tell me why engineers / Technicians use the ICL7660 on circuit designs ?? I would like to see an "Equivelent Circuit" of voltage conversion....................Regards.......Eugene

That is a neat chip, especially since you can drive it from an external oscillator, which we want to avoid unsynchronized signals floating around. The limitation seems to be it doesn't provide too much power, especially at high efficiency. But I'm interested in the idea of using power conversion somehow to use more convenient batteries and waste less power. TGSL wastes a lot of power going from 12V to 8V.

-SB

[ivconic]

Power drain is actually not an issue, especially at TGS/TGSL.
With last audio mod (2xBC547+BD140) it bairly drains 22mA up to 30mA in some cases. Conversion from 12 to 8 volts also is not an issue.
On TGSL, Delta Pulse and few other detectors, i am always using small accu. 12V/1.3Ah. So it lasts for days on terrains outdoor. Last time i checked it, it was my 5-day expedition, without charging i worked with TGSL approx. 10 hours per day, 5 days... So..it is not an issue at all.

Refering 7660...it is cute, but if you need more power than 78S40 is better solution. It costs
some 40 eurocents in local shops.

[ivconic]

Heck! I forgot to attach photo today!?
Here it is;

[simonbaker]

Power drain is actually not an issue, especially at TGS/TGSL.
With last audio mod (2xBC547+BD140) it bairly drains 22mA up to 30mA in some cases. Conversion from 12 to 8 volts also is not an issue.
On TGSL, Delta Pulse and few other detectors, i am always using small accu. 12V/1.3Ah. So it lasts for days on terrains outdoor. Last time i checked it, it was my 5-day expedition, without charging i worked with TGSL approx. 10 hours per day, 5 days... So..it is not an issue at all.

Refering 7660...it is cute, but if you need more power than 78S40 is better solution. It costs
some 40 eurocents in local shops.

Yes, if you have 12V battery anyway, not matter. But TGSL could run on 9.6 for example, more convenient with better regulator chip or other power scheme. 7660 looks like it only good for 10 mA I think, not sure. Less important than solving audio problems though!

I am trying to decide on best PCB for me so I can really test real MD -- waiting for Eclipse next PCB, I think has bigger space for components. Other suggestions welcome.

Cheers!

-SB

[eclipse]

Lateley I am so busy I've been to the forum 2 times in 3 weeks! Sheesh this work of mine is driving me crazy! I freezed all the work untill Christmas vacation hopefully. Cheers.

[simonbaker]

spacious PCB

Power drain is actually not an issue, especially at TGS/TGSL.
With last audio mod (2xBC547+BD140) it bairly drains 22mA up to 30mA in some cases. Conversion from 12 to 8 volts also is not an issue.
On TGSL, Delta Pulse and few other detectors, i am always using small accu. 12V/1.3Ah. So it lasts for days on terrains outdoor. Last time i checked it, it was my 5-day expedition, without charging i worked with TGSL approx. 10 hours per day, 5 days... So..it is not an issue at all.

Refering 7660...it is cute, but if you need more power than 78S40 is better solution. It costs
some 40 eurocents in local shops.

78S40 is nice to know about. What is efficiency, I could not tell from spec? Also did not see how to sync to MD oscillator which I think is important. Seems everyone is busy, me too, but still working on TGSL -- slowly.

If Eclipse has TGSL PCB without ground plane (tiny channels) please post, I'm interested! Or can anyone recommend which PCB is good for bigger components?

Cheers,

-SB

[ivconic]

... This is from White's Spectrum ps.
You have here sync input.
Power...i am not sure, i will search for any data, but if it can supply Spectrum - it can supply any other descent "consumer" too, i guess.
Cheers!

[ivconic]

"...The device can drive external NPN or PNP transistors when currents in excess of 1.5A or voltages in excess of 40V are required...."

Yup!

[simonbaker]

... This is from White's Spectrum ps.
You have here sync input.
Power...i am not sure, i will search for any data, but if it can supply Spectrum - it can supply any other descent "consumer" too, i guess.
Cheers!

Thanks for reference looks good. Looks like they put a sync pulse into the capacitor timing input -- hey, if it works... This chip needs external coil "buck-boost" type looks like, 300uH not to big I guess, but other 7660 just need capacitors. Usually type with coil higher efficiency though I think.

Another design possibility if you're feeling creative instead of sync pulse is to let the voltage regulator free run and use it's oscillator to drive TX coil; an idea I'd like to try sometime.

Cheers!

-SB