IGSL

[golfnut]

Hi Davor,

I would have connected the fuse to the 8v rail.

Put the 15ohm series resistor cap combo out to the LHS and to power the osc.

This gives the Rx plus rail more isolation from the Tx signal.

Maybe ?

S

[Davor]

And here is the redox version that I'm considering as an interim stage. I also put a surge protector and a 10000uF instead of 7808, and 9V supply ... the way I see it.

Input can be set as symmetrical and switches can be 4053 - with no changes to the rest of the circuit.

I'd be delighted if someone jumps in and makes additional corrections.

[Davor]

Here is the last version of IGSL schematic, the way I use it ... more or less. I took freedom to correct some component values to get into the "garden variety" choice and that is the only difference to what I use now. So all resistors are from E6 and transistors choice is very limited.
I "forgot" to correct the components designations (R1 ...) so it may require some further improvement.
It may now appear more obvious that one GEB channel is completely redundant. In case it is deleted, there are only 3 bilateral switches employed, and that is inviting something like a 4053 and full wave switching. OK, that will be a next step.

[satdaveuk]

I am considering replacing a 7808 regulator with a 10ohm resistor and 10 000μF capacitor, and giving up 12V supply for the much more convenient one: 9V cube battery, 6LR61 or similar.
Now, why should I do something like that?
First off, I am a light user of a metal detector, and my longest single pass with a metal detector took about two hours. Doing that with a 9V battery in a series with 2 AA cells, and I could not deplete more than 2 such 9V batteries for most of the summer. Hence, high capacity battery packs are a serious overkill for my level of usage, my pocket, and my back.

I'll try it this way...
I think I can easily do that BECAUSE the most of the IGSL is using a stabilised source at 8V anyway. Only audio uses 12V, and it can work as well with much less.
Inspired by the scuba diving gear that forces you to switch to the reserve air once the criterion of main reserve is met, I'll use not one but two cubes and a switch to select either of the batteries or none (OFF).
In addition I'll put a surge protector ICP-N15 (or something) in series with the supply and a rectifier diode from ground to the + right after the protector to be sure I don't blow anything valuable when changing the batteries. These protectors come at half the price of a regular fuse, and they simply recover to the working state over and again. And they come with a very small footprint too.

How am I going to use it?
I'll run on one battery and when I start noticing that it is giving up, I'll just switch to another. After some time I'll switch back to squeeze the remaining few drops of juice from the first one. Alternatively I'll buy cheap rechargeable cubes in Lidl and use them without squeezing the last breath out of them.

Total cost? 2Eur for a 10000μF, 1/2 Eur for ICP-N15, 1N4005 and a resistor from my beloved furda.

Good idea using less juice, seeing alot more of the icp-n15 etc these days in security equipment.

[Jerry]

Another alternative would be regulating the plus and minus supplies to 5 volts and running everything with +- 5 volts except for Osc. & audio at 9 volts. As is recall there are some Tesoro models already doing that but dont have time to look right now so I could be wrong.

Anyway, that is one of the schemes I have been thinking about but have not actually tried yet.

Jerry

[Davor]

I am considering replacing a 7808 regulator with a 10ohm resistor and 10 000μF capacitor, and giving up 12V supply for the much more convenient one: 9V cube battery, 6LR61 or similar.
Now, why should I do something like that?
First off, I am a light user of a metal detector, and my longest single pass with a metal detector took about two hours. Doing that with a 9V battery in a series with 2 AA cells, and I could not deplete more than 2 such 9V batteries for most of the summer. Hence, high capacity battery packs are a serious overkill for my level of usage, my pocket, and my back.

I'll try it this way...
I think I can easily do that BECAUSE the most of the IGSL is using a stabilised source at 8V anyway. Only audio uses 12V, and it can work as well with much less.
Inspired by the scuba diving gear that forces you to switch to the reserve air once the criterion of main reserve is met, I'll use not one but two cubes and a switch to select either of the batteries or none (OFF).
In addition I'll put a surge protector ICP-N15 (or something) in series with the supply and a rectifier diode from ground to the + right after the protector to be sure I don't blow anything valuable when changing the batteries. These protectors come at half the price of a regular fuse, and they simply recover to the working state over and again. And they come with a very small footprint too.

How am I going to use it?
I'll run on one battery and when I start noticing that it is giving up, I'll just switch to another. After some time I'll switch back to squeeze the remaining few drops of juice from the first one. Alternatively I'll buy cheap rechargeable cubes in Lidl and use them without squeezing the last breath out of them.

Total cost? 2Eur for a 10000μF, 1/2 Eur for ICP-N15, 1N4005 and a resistor from my beloved furda.

[bernte_one]

ahh ok

with sprint layout i can work
i have already the files here

thanks for your time and work

i will see if i can bring this project to german forum
i know there two person which are here too

maybe i can recrute some more there to make more evolution on diy projects like this

there was already the idea to assemble a spectrum analyzer - not bad

regards

[ivconic]

hello ivconic

can you please post last pcb layout files for express pcb

i think i will try express pcb (at moment sprintlayout)
thanks

No, i am having pcb file only in Sprint Layout format.
Kind a odd; but i am drawing schematics in ExpressPCB(SCH module included) and all my pcb's i am drawing in Sprint Layout 5.
Somehow i adopted those two for separate jobs.
ExpressPCB (SCH module) is most suitable for me for drawing schematics and SL5 is most suitable for me for drawing pcb's.
So i don't have pcb layout in ExpressPCB.

[bernte_one]

hello ivconic

can you please post last pcb layout files for express pcb

i think i will try express pcb (at moment sprintlayout)
thanks

[ivconic]

Reasonable.
No need to hurry, take your time.
Cheers!

[Davor]

I did already in post #1404, but with plenty of comments and some rubbish copy/paste extra that I missed to clean prior to posting.
I'll clean it one of these days.
I have an anniversary situation today, and my XYL would make a big fuss if I play with electronics instead

[ivconic]

And IGSL schematic in EpxressSCH format:

[ivconic]

BTW, in case you can't find installation; it is here:

http://www.expresspcb.com/ExpressPCBHtm/Download.htm






...

[ivconic]

I kind of left my PCB routing skills back in p-cad times, so I'll gladly leave that part to, well, anybody else. In lieu of PSpice I switched to LTspice and became fond of that program. I'll gladly share all that I learned while building my IGSL.

No, i don't mean you to draw new pcb, just to draw your corrections on existing schematic.
I posted schematic made in ExpressSCH here.
All you have to do is to install ExpressPCB software (including SCH part too) and open my file with it. Than to input your corrections and repost file again here.
That's why i almost always do post all my working files here : so to others can easily manipulate with them, input own corrections and share with others.
I hope it is easy job for you and others.
I am pushing ExpressPCB (SCH part actually) here on these forums, for long time ago, simple because i think it is most easiest software to work with.
It has everything that hobbyist may need. Inputing symbols and whole schematic is indeed very easy.
After all; that software is completely FREE and downloadable from it's official site.
...
So what i want to suggest again is; you to input your corrections in existing .sch file and repost it here.
Cheers!

[Davor]

I'm willing to consider suggestions Davor, but I do not know the timing used for a full wave detector!

It is exactly the same, except that the signal from the preamp is supplied in counter phase as well, and a switcher toggles between phase and counterphase. From the PIC point of view it is exactly the same. The advantages include lower losses, less offset troubles, better common mode handling, and it is by all means more sexy.

IGSL on the GEB adjustment it is the same on both channels?

Not in the original because Ivica had an otherwise good idea to sense earth by slightly underadjusting the GEB in a Fe channel. Trouble with such idea is that it requires an additional control, and in most cases you'd not use this feature anyway. In case GEB is perfectly adjusted in both channels (no underadjusting in Fe), they'd be switching at the same angle, so it can be joined in a single GEB, and make a whole shebang less complicated.
Besides, a handy 4053 has 3 switchers inside - just enough for GEB + two Disc channels.

PS: I prefer an independent oscillator which I synchronize the PIC.

There is nothing wrong with independent oscillator as long as it supplies phases correctly. In fact, controlling delay of the phase is more exact means of supplying vectors for discrimination, because the eddy currents do the very same thing - they delay. There is a potential problem of rising phase noise in 1/f region, but I guess it also depends upon the granularity of such delay. With high clock it might be just fine. Having a Tx fed by an amplified fraction of a system clock would produce no phase noise at all.
In such cases analogue is often better than digital.

Torque LC has its own frequency, and also much less harmonic

You may keep the LC tank at Tx even with forced oscillation at the clock fraction frequency. In such case it works as a filter and provides energy conservation. In this configuration it can provide even cleaner signal than the self-oscillating Tx. Just a thought.
Basically I have nothing against keeping the most analogue parts and just improving the binary ones, such as phase switchers. It would enable forking the project into a pure analogue one, and a PIC meld.