Ivconic Fisher Gold Bug

[Op04]

Dear OP04!!!!!!
Thank you!
I'll try to make it work! I'll post the results!

Dear Andre,, You're welcome! So exciting to see the result!!

[Andre]

Dear OP04!!!!!!
Thank you!
I'll try to make it work! I'll post the results!

[Op04]

Dear Andre, glad to see this progress. Just looking that schematic similar to sascho PID here's drawing from master Ivconic, try if that work.

[Andre]

Dear friends,

I got back to work on the Fisher Gold Bug I project perfectly adapted by our dear Ivconic. I got great results, but as with the original Fisher design, there is no iron discrimination step as there is in the Gold Bug II. Does anyone have any idea how a discrimination stage could be added to the circuit, which I leave attached to the post?

[Andre]

I try to figured out. Please correct me if I'm wrong, just want to keep this thread alive,, so the frequency that send to 4013 will do flip-flop (one part goes to tx another one to demodulator) as well as divided half in the same waveform (74.21 : 2 ) : 2 = 18.55khz while the 4053 is powered ON by the pulse carry from 4013 and switch ON signal from the receiver and goes to bandpass filter

You are right!!!!!

[Op04]

Can anyone explain the specific working principles of 4013 and 4053? Thank you

I try to figured out. Please correct me if I'm wrong, just want to keep this thread alive,, so the frequency that send to 4013 will do flip-flop (one part goes to tx another one to demodulator) as well as divided half in the same waveform (74.21 : 2 ) : 2 = 18.55khz while the 4053 is powered ON by the pulse carry from 4013 and switch ON signal from the receiver and goes to bandpass filter

[jeep6789]

Can anyone explain the specific working principles of 4013 and 4053? Thank you

[Andre]

If you added a 3.9k resistor from the inverting inputs to what they are calling VDD on the original schematic then you would have a buffer with a gain of 1 with less noise and the offset pots would be much easier to adjust.

DavidB,

There was no significant change in the adjusts, but I left the resistors there.

[Andre]

If you added a 3.9k resistor from the inverting inputs to what they are calling VDD on the original schematic then you would have a buffer with a gain of 1 with less noise and the offset pots would be much easier to adjust.

I can try this!
Thanks!

[DavidB]

If you added a 3.9k resistor from the inverting inputs to what they are calling VDD on the original schematic then you would have a buffer with a gain of 1 with less noise and the offset pots would be much easier to adjust.

[DavidB]

On the original schematic, the op amps that are connected to each side of the ground balance pot look like they should have an additional resistor connected from the inverting inputs to ground if they are supposed to have gain. The 1 meg resistor and 100k pots only to adjust the offset. It looks like the gain would be .0039 the way it is.

[Andre]

Ok Andre, I think with your progress here you have done a good job, thanks to Ivconic for giving us the modified GB scheme. If I have time I think I can build PCB, perhaps someday I'll post here. Your plan with PVC pipe, I've done it before, It's heavy to my arms, better if you use Elbow Crutches plus putting PVC on the lower rod, the bottom end is mostly 20mm diameter shaft, I put PVC at the lower end. Again, thank you for your updates of this project!
[ATTACH]54766[/ATTACH]

Great!!!!!!

Elbow crutches - How come I didn't think to use this thing?

Thank you!!!!!

[Op04]

Dear Op04,
Like the other topic (https://www.geotech1.com/forums/show...l-gold-nuggets), I did not build PCBs using any PCB software . My PCBs were drawn manually. This PCB should have been made in a double-layer board because there are too many jumpers on the component side. I think it will stay anyway. I'm going to put it in a box and build its rod with a PVC pipe. I am sorry for not helping you in this part, but I believe that you will have no difficulties in designing your PCB using the diagram provided. Let me know if you decide to build. I don't think you will be disappointed, since his sensitivity is very good.
I would like to remind you that good sensitivity is related to the construction of coils. I don't know if using other coils with different specifications, the sensitivity will be the same.

Ok Andre, I think with your progress here you have done a good job, thanks to Ivconic for giving us the modified GB scheme. If I have time I think I can build PCB, perhaps someday I'll post here. Your plan with PVC pipe, I've done it before, It's heavy to my arms, better if you use Elbow Crutches plus putting PVC on the lower rod, the bottom end is mostly 20mm diameter shaft, I put PVC at the lower end. Again, thank you for your updates of this project!

[Andre]

Dear Op04,
Like the other topic (https://www.geotech1.com/forums/show...l-gold-nuggets), I did not build PCBs using any PCB software . My PCBs were drawn manually. This PCB should have been made in a double-layer board because there are too many jumpers on the component side. I think it will stay anyway. I'm going to put it in a box and build its rod with a PVC pipe. I am sorry for not helping you in this part, but I believe that you will have no difficulties in designing your PCB using the diagram provided. Let me know if you decide to build. I don't think you will be disappointed, since his sensitivity is very good.
I would like to remind you that good sensitivity is related to the construction of coils. I don't know if using other coils with different specifications, the sensitivity will be the same.

[Op04]

Hi guys! This scheme is the best I can get! According to the coil I built, the sensitivity is very good and it was through it that I made the modifications. Perhaps with a coil ready, the detector does not have the same sensitivity. Unfortunately, I don't have a Fisher Gold Bug to compare. So, I leave this contribution here. I didn't have time to redesign the original layout, but I believe that everyone will understand the changes.

P.S.: As the previous diagram, I used your power supply with lm7806 and lm317 for 2.5V

Dear Andre,, Thanks for enlightenment for ivconic gold bug... Would you share your PCB according your diagram upload above? Thank you very much!!