Looking for Goldscan 5c by Eric Foster schematic

[6666]

With 4x4538,s and GB, it may be tuneable for the mineralisation here. I am interested in trying to adapt another 2x74hc221's to the Hammerhead to achieve this. I will study this more.
Here is the GS4 with audio and 1k to earth missing on some schems.

Thanks for your clarification gentleman.

There are other bits missing to.

[Tim]

Can you elaborate please 6666 ?....

[eclipse]

looking at the 2 opamp protection diodes... One of them must be in reverse?
all those timing parts can be replaced with 1$ processor... And yeah that schematic is missing power supply

[Tim]

Papa Alex's schem asterix's this as true to the original GS4 board, however others have them reversed.
Now, a processor able to calculate 4 samples-that would be equivalent to a lamebin, wouldn't it? Perhaps needing complex and expensive complimentary circuitry, and extensive programming and electronics knowledge to implement? Perhaps mitigating many hobbyists achievability, and any percieved design compaction??
Although I am an old stick-in-the-mud, I am really trying to embrace micro-processors, so perhaps you could run up a quick sketch of this $1 processor design?
I am going to try to make the PickiniV4 when my pickit3 arrives-my baby step toward micros.

[eclipse]

I have the C code for the MCU, it will need slight adjustment for this (or other circuit) but I believe it won't be hard.
I've tested it this summer and it worked.

Bad thing is I don't have proper timing diagram generated by GS 4.
Otherwise If someone is able to provide such, I can modify the source and supply some programmed PICs.

Components in red can be replaced by the MCU.
changes.pdf

[greylourie]

If you want to keep to the values of the original GS4 perhaps use a 450-550 pps tx range (important to have some range of adjustment so user can adjust out interference/emi etc), and use some thing like a 200µSec tx pulse width. I don't have info to hand on original delay range to first sample, but maybe something like 15 - 35µSec. And follow with the timings for the samples and the respective delays posted by Jose. http://www.geotech1.com/forums/showt...627#post150627

[6666]

Can you elaborate please 6666 ?....

There have been several schematics produced, some had missing grounds, missing resistors , missing caps, the power supply was modded, and the switches were confusing,
I think it was JOSE who got one to work after a lot of mods, if you have a carefull look through this thread, you should pick up what's missing.
There has been much discussion about the schematic over the years on other forums as well.
A pcb drawing was produced, but I never pursued it because of the uncertainty of the project.

http://www.geotech1.com/forums/showt...AN-4-Schematic

[Tim]

Thank you very much Eclipse! Your diagrams make it fathomable for me, and I am grateful. From this and the GS design, we could extrapolate a ground balance/ignore design applicable to other micro- based designs. Something seen as largely irrelevant to regions with "mild" ground, but wholly essential in places like Oz.
6666 and greylourie, thanks for those link-ones I definitely needed to review.

[eclipse]

One note: I used 4504 level shifter for my board with schematic above because the micro can be powered only by +5V and 0/+12V were needed in my case.
So my point is there might be a need for such shifting here as well, haven't go through the schematic.

[devilpookie]

Obviously not a schematic but might help somebody.

[greylourie]

There have been several schematics produced, some had missing grounds, missing resistors , missing caps, the power supply was modded, and the switches were confusing,
I think it was JOSE who got one to work after a lot of mods, if you have a carefull look through this thread, you should pick up what's missing.
There has been much discussion about the schematic over the years on other forums as well.
A pcb drawing was produced, but I never pursued it because of the uncertainty of the project.

http://www.geotech1.com/forums/showt...AN-4-Schematic

Follow the posts between Michael (mschmahl) and myself, we walked through the alexismex schematic (I think) using Michaels working original. Only a few omissions needed clarifying.
That thread you linked to has alot of good information. Maybe its better to simply study how it functions, and apply that understanding to one of the popular projects on Geotech, by adding the additional timing and channel....

[Tim]

Thanks eclipse. Thanks devil. Thanks again greylourie. All very useful.

[mschmahl]

I think this schematic is the most correct schematic.

and this one is ok also, only with a 5534.GS-4 mit RV bezeichnung.pdf

I have updated my original Goldscan with the right IC´s so you can solder (leave) out a lot of trimmers and resistors. It works better than before.
And it is much easier to set it up right for successful disc.

[kt315]

good thread but nothing new

[Jose]

Goldscan 4 is a feasible project to build, you can trust the scheme PaPa Alex.
Only you need to connect to GND drains, the J113 and 470K resistors add both channels.
I add also an R 10K and a capacitor 1 nF that worked best setting GND. See the diagram, the circles marked in red.
Then, you can improve the front with 5534, or even better with 5532, as uses the HH2, or Minipulse.
It can be installed in one 7660 source instead of 555, as already discussed above.
The main problem in this project is that do not have a reliable PCB, is the cause of much noise when making this project.
It would also be advisable to make the entire source in a separate PCB as the original, in order to keep away the noise.
It is a sensible, stable detector and removes fine red brick.
When basically understood as the GS4 works, you can try some mods that improve performance, but is a project that must be done long term.
It is not a weekend project or even a single winter, unless you are an expert.
It is important also the right fit, and fast coil must be.
Jose