Voodoo Main Discussion

[Qiaozhi]

@Qiaozhi,,,Regarding the depth that the Voodoo is capable of, what would be a reasonable estimation of depth say for a 7" coil compared to a 9" coil please? Personally I'm not looking for any extreme depths as such as I think around 8" depth is ample for me for Inland detecting. The esimation will help give me an idea of which coil/coils to build for testing once I've built the Voodoo. Thanks George, Regards, Marty.

I would lean towards using a 9" coil, as it's a good compromise between sensitivity to small targets and ground coverage. Although I did some comparison tests in Chapter 6, I wasn't focused on depth measurements, but more on identifying non-ferrous targets amongst ferrous trash. There is still a lot of room for experimentation with different coils to find the optimum solution.

[MartyJ1963]

Thanks Qiaozhi. I've already begun to make an 8" coil based on the Inductances of the 'Small coil' in your book. I'll make a 9" template later so I have something to compare it to once I've built the Voodoo project. Just waiting on obtaining a PCB now. Regards, Marty.

[silverdog]

Thanks Qiaozhi. I've already begun to make an 8" coil based on the Inductances of the 'Small coil' in your book. I'll make a 9" template later so I have something to compare it to once I've built the Voodoo project. Just waiting on obtaining a PCB now. Regards, Marty.

They arrive tomorrow not sure why they had a little holiday in Germany but there you go

[MartyJ1963]

Nice one Andy! Could you please release the prices of the PCB's (and battery charger pcb) and the programmed chips, if you decide you're doing those also? Thanks, Regards, Marty.

[surfdetector]

Thanks Qiaozhi. I've already begun to make an 8" coil based on the Inductances of the 'Small coil' in your book. I'll make a 9" template later so I have something to compare it to once I've built the Voodoo project. Just waiting on obtaining a PCB now. Regards, Marty.

Hi Marty,
It would be great if you could do a post with some pictures of the steps involved to make your coil. That would be a great addition.
Cheers

[lamoiz]

They arrive tomorrow not sure why they had a little holiday in Germany but there you go

hi silverdog, I order as soon as you put this on your site !!!

[MartyJ1963]

@SurfDetector,,,I will take photos of the steps I take to make my coils as I intend making quite a few (As George did) to experiment with and compare depths/sensitivity etc,,,Don't think I'll be able to start building till at least next week though as I've been repairing the house (From a flood) for the last 6 weeks. Hopefully it'll all be completed by the weekend. PS- Enjoyed your build videos on You tube,,,great job! Regards, Marty

[bernte_one]

Hmm yummy yummy pcbs has arrived

[lamoiz]

Hmm yummy yummy pcbs has arrived
[ATTACH]53583[/ATTACH][ATTACH]53582[/ATTACH]

it's beautiful ...

[lamoiz]

Hi Marty,
It would be great if you could do a post with some pictures of the steps involved to make your coil. That would be a great addition.
Cheers

As soon as I have the voodoo pcb in my hands, I start my test coils, too.

[MartyJ1963]

@Lamoiz,,,It'll be great for everyone to exchange and compare coil data,,,This is going to be a top project and thread! Regards, Marty

[MartyJ1963]

@Qiaozhi,,,Just out of curiosity, how would we go about the shieldng of these coils? Would they be shielded in the same way as a VLF Concentric,,like 'Graphite' or similar? Thanks, Marty.

[Qiaozhi]

@Qiaozhi,,,Just out of curiosity, how would we go about the shieldng of these coils? Would they be shielded in the same way as a VLF Concentric,,like 'Graphite' or similar? Thanks, Marty.

Shielding is advisable, using whatever method you prefer.

[MartyJ1963]

Thanks Qiaozhi. Do both coils have to be shielded separately or both coils as a whole? And does the shield wire go to 0v? Thanks, Marty.

[Qiaozhi]

Thanks Qiaozhi. Do both coils have to be shielded separately or both coils as a whole? And does the shield wire go to 0v? Thanks, Marty.

If you use graphite as the shielding inside the coil shell then this will shield both loops. Alternatively you can shield each loop independently using conductive tape.
The shield should be connected to 0V (which is Batt+ in the Voodoo project).
Here's a post describing Eric's method for shielding coils ->
https://www.geotech1.com/forums/show...821#post254821