Voodoo Main Discussion

[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.

[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.

[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.

[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

[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

[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]

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

[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]

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]

Why you put giant resistors all over the pcb?
No need for that.

I was also wondering the same thing, as he previously said:

"I bought all the best parts I could that digikey had waterproof 5 pin male and female for the RG58U coax all gold contact ic dip sockets all gold test points multi colored screen waterproof push buttons and switch the best caps and resistors I?m at about $240 so far lol I want to make it so whoever just sees it asks about it let alone begs to use it"

[ivconic]

Why you put giant resistors all over the pcb?
No need for that.

[SilverSurfer17]

Got my display going temporarily until i decide what color i want to light it up here is the common blue

[Altair]

Hmm. Haven?t tried just two triggers but the polarity of the main clock is inverted to start with... so I added the 3rd trigger to have an odd number and flip it back. Maybe it doesn?t matter?

Don,
two or three triggers rely on where they are connected to main PI clock. if the main PI clock is get from Q1 collector, only two trigger are enought, if I don't wrong.

[SilverSurfer17]

What part of this forum do i ask questions about coils like has anyone messed around with multiple coils as in instead of using 1 15inch coil using like 5 3 inch coils is there a spot on this forum for people who try odd ball stuff or like if you want to move faster and detect instead using one head unit with one coil 3 head units with 3 coils so you have more coil covering the surface area so you can move faster use smaller coils cover more ground and still detect small items

[SilverSurfer17]

Does anyone know if they make a pcb for the lcd rheostat so you can mount it without having to worry about breaking the legs off or do you have to use that blank breadboard and build one same with the volume control ?