Voodoo Main Discussion

[lamoiz]

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

it's beautiful ...

[bernte_one]

Hmm yummy yummy pcbs has arrived

[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

[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 !!!

[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

[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.

[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]

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.

[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.

[Qiaozhi]

I proof-read the entire Voodoo book twice, still missed things. I think a better proof reader is someone who is not very familiar with the topic.

Your assistance was hugely appreciated, especially as you caught a huge number of errors. In particular, your comments on Appendices C, D, and F were invaluable. Someone not very familiar with the topic could not have helped in that case.

Maybe a combination of familiar and not familiar is the key to an error-free result.

[Carl-NC]

Yes, I know. Same thing happened with ITMD. Carl and I read and re-read it 100s of times.

I proof-read the entire Voodoo book twice, still missed things. I think a better proof reader is someone who is not very familiar with the topic.

[MartyJ1963]

@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.

[Phantom]

Done!
Glad to be of service.

Thank you very much George

Regards

Phantom

[Qiaozhi]

i want to draw a concentric coil shell for 3d printing

it should have 280mm outer diamater,
what inner diameter is best choice / relation ?

Well that's a good question, and one that I raised at the end of Chapter 7.

Personally I like the ratio used by the Laser and Tesoro coils.
Using the outer diameters of the loops as a reference, the Laser has 9" (229mm) and 3.75" (95mm), which is a ratio of 2.4:1.
Whereas the 12" (305mm) White's coil has an inner loop [outer] diameter of 6" (152mm), which is a ratio of 2:1.
I find that the smaller diameter inner loop provides better target separation. However, having a smaller diameter requires more turns to achieve the same inductance.
Based on a ratio of 2.4:1, this indicates an inner loop [outer] diameter of 117mm for the 280mm coil.

[Qiaozhi]

Gerorge,

Yes, this is the clear example of a typing error. Then I did not know if trying to correct it would lose my account


I would be very grateful if you made this change. Thank you very much


Cheers to all

Phantom

Done!
Glad to be of service.