Voodoo Main Discussion

[godigit1]

I think that the 2n2222 is actually the more robust part.

I should have left them alone they were working I had used them on the voltage level converters.

I replaced them then decided to do a flux clean of the whole board and lost my + 5 rail I've been replacing parts to no avail so far.
Pic is working but my sync pulse is off.




.

[ivconic]

I should have left them alone they were working I had used them on the voltage level converters.
I replaced them then decided to do a flux clean of the whole board and lost my + 5 rail I've been replacing parts to no avail so far.
Pic is working but my sync pulse is off.
[ATTACH]54100[/ATTACH]
.

I had exactly the same problem.
I put BC547/BC557. Than i replaced them with 3904/3906.
Still no +5V. I traced sync signal from PIC till the LT1054.
It was weird looking but it was there.
Same as on your blue trace.
Replacing 78L05 with 7805 solved problem.
Weird, no logic...

[tomec123]

The wire sizes for RX / TX and possibly the number of turns would be very interesting for the IDX-Pro project. That would really help a lot. If you already have the Black Max 950 on ;-)

[Matt_Rowe]

here is a link to the TGSL thread with the downloadable docs on how to build the coil, a concentric, Rx, TX, And Bx or bucking with all the wire sizes, turns, ect.
I have downloaded the files and they are written perfectly with wire sizes, lengths, and pics of the complete process from Dbowers who makes the coil shells and posts here.
Maybe not what people need for a coil, this is from Dbowers, I have attached a
Here is the link, its at the bottom of downloads, in sticky on top of page HERE

[6666]

hi, not had a lot of time to work at the moment but, I did work a little bit anyway .. So, question, in your opinion ... who is the winner in the photo ?? I have the answer![ATTACH]54086[/ATTACH]
for information, all tested with the same capacity of 21.6nf, and make all the same values or almost. the DD tx = 370uh Rd 550r RX = 11.11mh. Omega TX = 355uh Rd = 400r RX 10.96mh, and superD TX 389uh Rd 550r Rx 10.6mh (5.3 + 5.3) the idea of all this is to share the experience and value if one shape is better than another.
they are also made with the same wires of Litz 175/46 on the TX and 0.18mm on the RX otherwise it does not make sense ...

Hi lamoiz, thats really great work thanks, for the null,
did you use the Voodoo in hybrid mode ?,
what part of the schematic did you monitor to watch the null ?, and did you just go for simple minimum null ?
with the super D, the cap was in parallel with the two RX windings ?
why did you choose ~11 milli Henry for the RX value ? are they all 3 coils roughly the same outside diameter ?
Happy New Year All.

[lamoiz]

Hi lamoiz, thats really great work thanks, for the null,
did you use the Voodoo in hybrid mode ?,
what part of the schematic did you monitor to watch the null ?, and did you just go for simple minimum null ?
with the super D, the cap was in parallel with the two RX windings ?
why did you choose ~11 milli Henry for the RX value ? are they all 3 coils roughly the same outside diameter ?
Happy New Year All.

the super D is a little smaller than the omega and the DD, 11mh to resonate at 10.5khz with a capacity of 22nf, on the three coils I made the same values in order to be able to compare the shapes. to set the null, in PI mode, position the rx coil (or the two rx on the superD) and look at the waveform on tp3, then on tp4, then switch to hybrid mode without touching anything, and watch the signal on tp5 for an adjustment of the waveform .. here I did it like that ,, I don't know if this is the right method, but it is the one that I did .. on the super d, yes the capa is parallel to the two coils series.
for the super D, you have to pay attention to the direction of rotation of the electro fields, it is not always easy to locate the right connection wires.

[dfbowers]

While waiting for my PCB and PIC to arrive I decided to build a concentric except I went for a more conventional 360uH TX and 6.9mH RX coil. To test it I attached it to a modified Surf PI Pro with a split TX and RX. To my amazement it worked great for a disc channel but required reduced gain. So I figured why not just build a separate disc channel and have an analog version of the VooDoo? I am just using the existing PI channel as an equivalent GB channel and borrowed some of George’s idea from the VooDoo project. I am just merging the two channels just like the Raptor, TGSL or Whites classic with a pair of LM393s. The only real challenge was getting the frequency response of the GB and disc channels close to the same. Also.. Resonant frequency of the RX channel doesn’t seem to matter much as long as the sample delay and sample pulse can be adjusted to sample at the correct time.
Too many ideas from on George’s books to post here but I can show that it works.
https://youtu.be/9aqxGrFK9fo


So, here is a little demo of how it works. It deals with the ground signal quite well and can disc iron with an analogue meter.

[6666]

Hi lamoiz
Thank you your information is very helpfull, I may have more questions later, cheers.

[dfbowers]

Maybe this style of coil, this from don bowers pdf i downloaded on making an IDX Concentric Coplaner coil.
[ATTACH]54088[/ATTACH]

If Don does not want met to share his image, i wll remove it, it is from his pdf i downloaded that is the whole process to build one of these, and who better to make the coil shell also, which i have bought some shells from him and they are as good or better than whites, or anyone else also,I dont have his permission to share the pdf so i wont.

This for the whites classic series which is a vlf, but it does use 5 wires like a whites.
Maybe have to build 2 coils for voodoo, one for vlf, and one for PI.
I have learned from my experience that when something can do multiple things, it cant do one thing the best as to say.
When i took my detectors out prospecting, i always took 2, my whites goldmaster, which ran at 50khz, and my tesoro which ran at 25khz.
Goldmaster for small gold, and Tesoro for larger. Both vlf. i would switch them. Goldmaster for smaller stuff, Tesoro for deeper bigger.Goldmaster more sensitive.

No problem with the image! That image shows up everywhere. Glad someone else could use it.

[6666]

While waiting for my PCB and PIC to arrive I decided to build a concentric except I went for a more conventional 360uH TX and 6.9mH RX coil. To test it I attached it to a modified Surf PI Pro with a split TX and RX. To my amazement it worked great for a disc channel but required reduced gain. So I figured why not just build a separate disc channel and have an analog version of the VooDoo? I am just using the existing PI channel as an equivalent GB channel and borrowed some of George’s idea from the VooDoo project. I am just merging the two channels just like the Raptor, TGSL or Whites classic with a pair of LM393s. The only real challenge was getting the frequency response of the GB and disc channels close to the same. Also.. Resonant frequency of the RX channel doesn’t seem to matter much as long as the sample delay and sample pulse can be adjusted to sample at the correct time.
Too many ideas from on George’s books to post here but I can show that it works.
https://youtu.be/9aqxGrFK9fo


So, here is a little demo of how it works. It deals with the ground signal quite well and can disc iron with an analogue meter.

Good work thanks for the info. Could it turn into a group project ???

[dfbowers]

Good work thanks for the info. Could it turn into a group project ???

I think so.. I will run it past George. I can have him look at the schematic once I clean it up.
As far as the actual schematic there is nothing special. His original concept is used though.. just did it in analog.

[6666]

I think so.. I will run it past George. I can have him look at the schematic once I clean it up.
As far as the actual schematic there is nothing special. His original concept is used though.. just did it in analog.

Excellent, thanks.

[Qiaozhi]

While waiting for my PCB and PIC to arrive I decided to build a concentric except I went for a more conventional 360uH TX and 6.9mH RX coil. To test it I attached it to a modified Surf PI Pro with a split TX and RX. To my amazement it worked great for a disc channel but required reduced gain. So I figured why not just build a separate disc channel and have an analog version of the VooDoo? I am just using the existing PI channel as an equivalent GB channel and borrowed some of George?s idea from the VooDoo project. I am just merging the two channels just like the Raptor, TGSL or Whites classic with a pair of LM393s. The only real challenge was getting the frequency response of the GB and disc channels close to the same. Also.. Resonant frequency of the RX channel doesn?t seem to matter much as long as the sample delay and sample pulse can be adjusted to sample at the correct time.
Too many ideas from on George?s books to post here but I can show that it works.
https://youtu.be/9aqxGrFK9fo


So, here is a little demo of how it works. It deals with the ground signal quite well and can disc iron with an analogue meter.

It's not easy to tell from the video whether you're using a simple SAT, or single, or double-differentiating filters.
I've also tried analog versions of Voodoo with varying degrees of success.

[dfbowers]

My original PI circuit uses a SAT for the audio threshold.. that’s it. For the disc channel I’m using a single ended diff amp same method you use for the VooDoo. For the Disc channel, I’m pulling from the main clock on of the PI detector and using Schmitt triggers to adjust delay and sample width. Then just merge the channels with LM393s. I think I could get it to work on the Baracuda, Hammerhead or Surf PI.. I had to change a few thing on your disc channel though because the frequency response was different between my PI circuit and what you have in your book. I had to change the gains a little as well. It completely ignores brick which I think is close to a real ground signal. That makes me feel optimistic. I will clean up my schematic and send it to you .

[6666]

It's not easy to tell from the video whether you're using a simple SAT, or single, or double-differentiating filters.
I've also tried analog versions of Voodoo with varying degrees of success.

George do you think Dons project could be viable if it does not infringe your IP too much ?
I have both books by the way.