Voodoo Main Discussion

[6666]

Thanks GD, but first attachment is invalid.

[godigit1]

Hi Marty.
Here is some further info on the test coil I wouldn't call it a guide but should give you some food for thought.

First the forms,
I used embroidery hoops to make the bobbins they come in round and oval.
I used a 4 inch and a 8 inch and super glued 1/8 inch foam board to each side to make the bobbin's. Most are about a half inch thick.
you can also use them for coil shells if you wanted.
In this pic are a couple different ones the one standing up is cut in half to show you could use them for a thinner bobbin if you wanted.



The Rx coil is built first, always add extra wraps so you can adjust it to your desired inductance by removing wraps at the end.
I had intended to make the rx coil a verticle and started out that way but ended up just doing a spaced bundle kinda.
I wrapped 20 wraps then wrapped that with a layer of tape then 30 , tape 20, tape 30 for a total of 90 wraps.
I removed 10 to tune it to 2nH so 80 wraps 30 awg magnet wire.
Then you want to wrap the coil in one last layer of tape this time it needs to be double sided to hold the bucking coil in place.
The Scotch in the pictures is the only one I've had good luck with.

Next is the bucking coil,
I wrapped it from the top to bottom with 9 wraps it was figured for 7
I eyeballed the wire spacing and the double sided tape holds it in place so you do not need a spacer. Its a test coil a final production would be done a bit better.

Close up of the bucking coil.


Then Attached the rx and bucking coil to the Tx form.
I used double sided tape so I could adjust it if I wanted.
Cut a slot through the foam board on the Tx where you want it and cut a grove in the bobbin to inset the Tx wire.


Now wrap the base of the Tx spool with double sided tape and you can start the first layer.
I went 15 wraps keeping a space between the wires then another layer of double sided tape and 15 more wraps and a third layer of tape and 10 wraps.
for 40 wraps . I way over did it.
At 40 wraps though for info it was exactly 1nH inductance. I removed 13 wraps for a inductance of 385uh.

TX stack


Here is a top view if the coil you can see where I cut the slot to start the tx wind.



Now to null the coil you just remove a couple wraps and get it close as you can but do the final null in the shell so its attached to the cable and everything can be locked down.

Keep in mind this coil has never been tested I need to build a regular bundle with the same spec to compare to just to have a base line.

Looking forward to your video production good luck with all that.
Now to watch surfs vid and pass out.

[MartyJ1963]

Hi Alec,,,I came across your new video a couple of hours ago on you tube,,,,Great video on programming the PIC and very well put together,,Nice one! Thanks, Marty

[surfdetector]

As I wait for my Voodoo pcb to arrive, I decided to do a quick video on my YouTube channel on how to use a PicKit3 to load the Hex file onto the PIC. Obviously this is meant to guide people who may not be familiar with the process.

https://youtu.be/O9V8fmQWXe4

[MartyJ1963]

Thanks Godigit,,Looking forward to the guide/photos etc. Regards, Marty.

[godigit1]

Hi 6666 ,Marty.
Ill put something together comprehensive. I've taken Photos along the way.
I don't think anyone has made this coil that I know of. I've been playing with planar coils and wanted to try verticle stacks .
I remember way back Carl saying they had some advantages seemed like a good time to try as construction favors a concentric coils.

Here is the calculator I used for the stacked coil.

http://electronbunker.ca/eb/InductanceCalcML.html

[MartyJ1963]

@Godigit,,,,Thanks for your reply. It'll be great if you could post your construction methods of the particular 'Vertical stack' coil,,I'm really interested in having a go at this coil. I can see that I will be making a lot of different variations of coils for this particular project with the Voodoo being able to accept so many different inductances,,,really can't wait to get started on the build to actually be able to test all the coils I have planned to build already. I've never built this Vertical stack version so I'm looking forward to your construction guidance and actually building something different to test with the Voodoo. I've been spending the last few evenings learning how to use the software called 'Techsmith Camtasia' so I can incorporate my Voodoo build notes/experiments/coil builds and video logs into an actual full video log. Still playing about with it though at the moment but by the time I start building and taking notes, Photos, vids etc I should have some material to have a go putting it all tgether in one video. Thanks for taking the time to help us out with the construction details,,very kind of you. You stay safe and well too Godigit,,Regards, Marty

[6666]

Hi Marty,
I was short time to post this morning but if there is anything you want to know about construction method let me know.
I will say having the bucking coil wound around the bobbin in a flat manner made it super easy to null the coil by removing wraps.
Be Well

Interesting will have to study it.

[godigit1]

Hi Marty,
I was short time to post this morning but if there is anything you want to know about construction method let me know.
I will say having the bucking coil wound around the bobbin in a flat manner made it super easy to null the coil by removing wraps.
Be Well

[MartinB]

Sounds ideal for UK detecting where most of our available land is agricultural and heavily infested with deep iron such as plough points, horse shoes and other ferrous items. I will be interested to see if the Voodoo can detect a desired target which sits next to a ferrous object and also the recovery time from detecting a ferrous object to detecting a desired target.

[MartyJ1963]

Thanks Godigit,,,Appreciate it. I understand what you mean now,,,It's given me some ideas now to try out with the 16 strand wire I'll be using for my 3dss. I'll be logging everything I do and keeping a record so I'll post my results as I go along. I still can't start building yet as those 79L05's still haven't arrived yet,,they should've been here over a week ago. Thanks again for the pics and data. Regards, Marty

[godigit1]

That's 8 inch Tx 4 "Rx
Sorry

[godigit1]

Hi Marty,


this is the first one Ive built, in the picture everything is over wrapped a few turns.
Final #s are 30 awg 40/46 wire 27 turns 4" I.D
Tx 385uh Rx 2.04nH. 30 awg magnet wire. 8" I.D
Bucking coil ended up 6and about 34 turns with a final null at 0 to 800uV.

One down .

[MartyJ1963]

@Godigit,,,Do you have any pics of what a 'vertical stacked layered planer coil' looks please? I've never heard of one but it sounds really interesting! It may give me some more ideas too. Thanks, Regards, Marty.

[MartyJ1963]

Hiya George,,I forgot to ask,,Regarding the 'Waveforms' on Page 31 - Is there any chance you would be able to post the diagrams,,,I'm really struggling to read them with them being so small and even though I have scanned them at 600pi a lot of the writing etc still isn't legible enough. Thanks again, Marty.