Voodoo Main Discussion

[SilverSurfer17]

When ever i pulled parts in the past its had the wattage ratings for whatever i was stuffing nothing had wattage ratings on the parts list i searched to see if it made a difference and everything i searched said no so i got the highest wattage waterproof flameproof lowest % rating and of course saw the problem after they arrived ill replace them sooner or later to gain some room

[Qiaozhi]

When ever i pulled parts in the past its had the wattage ratings for whatever i was stuffing nothing had wattage ratings on the parts list i searched to see if it made a difference and everything i searched said no so i got the highest wattage waterproof flameproof lowest % rating and of course saw the problem after they arrived ill replace them sooner or later to gain some room

The Voodoo design is an advanced project for experienced metal detector builders, and one of the assumptions made was that you should know what you're doing based on having built previous PI and/or VLF detectors. You do not need to fit a 5W resistor where a 250mW device is adequate. Not only may the 5W resistor not fit in the allocated space, but the pins will most likely be too large for the PCB holes. Anyway, no-one ever said that the Voodoo Project was going to be easy. It was actually the underlying concept that I wanted to get across to the reader, without having to spoon-feed the basics.

So far I've generally seen some good feedback and ideas from Geotech members. In particular, one useful thing that Marty did when ordering parts was to note the pin spacings of the components. I thought that was a good idea, and intend to incorporate that into the component parts list of any future designs. Also, Don is exploring a slightly different approach, but based more or less on the Voodoo concept, and I'm interested to see how that pans out.

[SilverSurfer17]

Oh im not complaining i did this because it was advanced no shame in my game either i didnt have to post it i could ordered the right parts and put them in or not even shown the board in the picture as a matter of fact i could of came in here and never typed one word my point is im learning from what ive read its like having fuses like you said will see i dont like the test points i also ordered 1uf caps that are way to big i could make them work just to see what happens

[MartyJ1963]

Thanks for the compliment George,,it means a lot. Everything I've learnt about Detector building I've learnt from all the many good members here on Geotech and I'm still learning! I remember being over enthusiastic and super eager to get my very first detector build made (The Surf P. 1.2) back in 2016 and almost completely destroyed it! At the time, if it wasn't for Andy (Silverdog) helping me correct all my faults and teaching me to think about things more logically then I would never have learnt the 'better' skills I have now. It took me 2 Surf builds to finally get a working unit. I still made loads of mistakes building my 1st Minipulse Rev-D which I had to send to Andy who actually fixed it for me. With all his help, and the help of countless others on Geotech I didn't have as many problems after that. Every build after that became so much easier, less frustrating and much more enjoyable to build. Now I'm ''Totally addicted'' just like the rest of you all!!,,Lol. That's why I love this forum so much,,A library of different detectors to build,,an endless number of skilled people and builders who are kind and considerate enough to not just help the newbies better their skills but to further add to what I think is the best Metal Detector Forum on the Net. You never know, but the next ''Newbie'' could well turn out to be the next ''Go to'' guy that has all the answers we may all go looking for. Looking forward to advancing my Voodoo build further soon,,,one more house repair to complete!! Regards, Marty.

[SilverSurfer17]

Im going to be asking you all kinds of crazy questions about how to collapse the magnetic field faster how to get more amperage to the coil im loving this been wanting to learn more on hardware and software and i know if it wasnt for Tesla i doubt this would even be around so thats win win win also George i think i heard about you like decades ago if im not mistaken a few times yours is only the second book ive ever read besides A Man Out Of Time

[SilverSurfer17]

Albert Wore the same exact type of clothes every day he wore slip on shoes walk the same exact streets ate at the same places ordered the same food everyday he knew what he had to pay he had the exact change already to go

[waltr]

Hi everyone. Received the VooDoo book a week ago and now have read it through. Nice write up and especially liked the details in the appendixes.
I have the PCB on order from SilverDog. Hopefully it will arrive in another week or two. The US Post here has been very slow.

I had the concept of PI with resonance but never got good ferrous discrimination working. Was also working on doing everything after the pre-amp with digitail processing (using a PIC32).

Three thing George did that I never thought of are:
Mono PI TX/RX coil and LC resonant (VLF) RX coil.
Separate RX pre-amp.
Double differentiating gain stages on both PI & VLF.

After getting this VooDoo working as George designed it I may go back to using code to replace all circuits after the pre-amps.

[MartyJ1963]

Hiya George,,,Was it 'Polymer' whom you meant when you wrote about component pitch sizes? As I recall 'Polymer' posting a 'Voodoo_pitch_parts.pdf' in post #126 - Which I thought was a good suggestion also. Regards, Marty.

[6666]

The clue to the type of resistors to order/use are on the parts list page #87, at the top of the page it says RESISTORS 1%
this tells you to use 1% tolerance 1/4 watt metallic film resistors. (1/2 watt are fine to, just slightly bigger in size)
The PI coil damping resistor and the 1K series resistor R19 should be 1-2 watts as they can get hot .

The rest of the components are chosen by voltage rating above 12 volts and the foot print on the silk screen and pin width, 12 volts is the maximum rail voltage , so 16-25 volt electrolytic's and small MKT caps which are generally rated at 60-100 volts, just the same as most projects here, but there is nothing stopping you from useing other types
of components as long as they are the correct value.

[SilverSurfer17]

I didnt have the book yet i still dont wont be here until Thursday i just went by the parts list posted in #1 and all the values match accept the wattage and like i said i dont care ill check it out tonight if i can tune those trimmers going of the posts and see what happens if not ill start replacing the resistors until i do i also plan on buying other boards in the future i would of bought more when i ordered but i knew Silverdog wouldnt of had many on hand and i was right i got one i can mess around it while its 14 degrees outside even if i fry a trace ill just make a stronger trace ive been waiting a long time for a diy that can discriminate that i could mess around with

[Qiaozhi]

Hiya George,,,Was it 'Polymer' whom you meant when you wrote about component pitch sizes? As I recall 'Polymer' posting a 'Voodoo_pitch_parts.pdf' in post #126 - Which I thought was a good suggestion also. Regards, Marty.

I thought it was you, but it could have been Polymer ... or maybe both. Whoever had the idea first, it was a good one.

[billr]

What is going on here?

This thread is becoming overwhelming to the casual viewer like myself with a vested interest in the project. I hope the admin realize this. If not, then they should. In all honesty I have lost track of what is happening here. After much chat over how to program a PIC. A discussion that should have been allocated to it's own separate thread and now 'something' about making a new pcb or is this an addition to overcome the flaws in the original design? I truly have no idea what is going on.

Would someone kindly highlight to those not fixated on the thread on a regular basis what is actually transpiring?
41 pages to-date seems a little long to cover a build or is that proposed as a separate thread later when all the bugs are resolved?

Excuse my abruptness. But unless you are directly involved with this thread in real time, This will be a mammoth read to someone dropping by 1 year from now interested in building the detector.

Regards
Bill

[6666]

This thread is becoming overwhelming to the casual viewer like myself with a vested interest in the project. I hope the admin realize this. If not, then they should. In all honesty I have lost track of what is happening here. After much chat over how to program a PIC. A discussion that should have been allocated to it's own separate thread and now 'something' about making a new pcb or is this an addition to overcome the flaws in the original design? I truly have no idea what is going on.

Would someone kindly highlight to those not fixated on the thread on a regular basis what is actually transpiring?
41 pages to-date seems a little long to cover a build or is that proposed as a separate thread later when all the bugs are resolved?

Excuse my abruptness. But unless you are directly involved with this thread in real time, This will be a mammoth read to someone dropping by 1 year from now interested in building the detector.

Regards
Bill

so before we write anything we need to get your permission do we

[SilverSurfer17]

Buy the book it tells you just about everything you need to know and the few minor mistakes are covered in post #1 its this big because there are lots of people interested in George's design and welcome to the forum

[Qiaozhi]

This thread is becoming overwhelming to the casual viewer like myself with a vested interest in the project. I hope the admin realize this. If not, then they should. In all honesty I have lost track of what is happening here. After much chat over how to program a PIC. A discussion that should have been allocated to it's own separate thread and now 'something' about making a new pcb or is this an addition to overcome the flaws in the original design? I truly have no idea what is going on.

Would someone kindly highlight to those not fixated on the thread on a regular basis what is actually transpiring?
41 pages to-date seems a little long to cover a build or is that proposed as a separate thread later when all the bugs are resolved?

Excuse my abruptness. But unless you are directly involved with this thread in real time, This will be a mammoth read to someone dropping by 1 year from now interested in building the detector.

Regards
Bill

Hi Bill,

I fully understand your comments, and I did initially consider splitting off some of the conversations to separate threads. However, this leads to a lot of maintenance work that I really don't have time for.

The reality is that the book has full details of the project. In fact, more than you may even want to know. Any errors or important points noted by readers have been added to post #1, so there is no danger of missing anything. Of course, if you don't have a copy of the book, then it will no doubt be difficult to follow the discussions. But in that case, why would anyone be interested in this thread in the first place?

There have recently been discussions concerning a variant built by Don Bowers, and that's why you may see some talk about a new PCB. This is not an attempt to overcome any flaws in the original design, but just a slightly different approach. So the important point is that (for someone dropping by 1 year from now) the book and post #1 are really all they will need. If Don finds that his variant is successful in the field, then he may want to start a new thread for that particular design, but at the moment it still has relevance to the Voodoo Project.