Board coils discussion

Assembly instructions for the V1 chessboard.
Tony
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Board coils discussion

Post by Tony »

Suggestions for improvements, mistakes, hints here please.
bstott
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Joined: Wed Sep 19, 2012 5:28 am
Location: Pittsburgh, PA USA

Re: Board coils discussion

Post by bstott »

Question:
Does it matter the direction of the windings? I see the direction start in your photo. I might find it easier to wind in the opposite direction.

Request:
A final picture of a board coil with the windings complete. (You did give enough info.. It is just comforting to compare what we do to what you have done.)
Tony
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Re: Board coils discussion

Post by Tony »

The direction isn't important but you will find fitting the required number of turns on a bit tight. Once these kits are out I'll add some more photos to the instructions, hopefully I'll be getting my hands on a better camera soon to take a few high res photos.
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SpankyMcSpank
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Location: Oz

Re: Board coils discussion

Post by SpankyMcSpank »

Finally got some time to construct all the board coils... sanded them, washed them, dried them and then began the construction 8 units at a time.
Assembly is easy, follow the pictures in the tutorials, place a bit of superglue (I used Loctite 406 in the small bottle) in the groove and rotate it so it flows around with gravity and places a fine coat of glue. I also placed a couple of small drops onto the base piece securing it to the bobbin part.

Next winding the coils.. initially I threaded the wire through one of the mounting holes and wrapped it around the bolt shaft as per Tony's instructions, then wound on the 55 turns by hand.
Mostly it worked well but fingers got tired and had a few mishaps with dropped loops that needed careful recounting.
Over time I refined it, for me, to thread the wire , loop on bolt, then wound on 10 turns whilst holding it in my hand. After that I mounted the bolt in the chuck of a battery operated drill and used that as a stable base for the further winding of the coil and used my finger on top to count each loop as well as hold them in place as I counted in case a loop slipped off as did in earlier coils before I used the drill. I also tried using the drill on very low speed with some tape as a reference for counting, and it worked ok, but in the end it was easier to wind by hand but using the drill as a mount.

After all that, use a couple more drops of superglue to secure the wire, let set, remove bolts and start all over again :)

To be honest, although repetitive, I did enjoy the coil winding !! Took 2 days part time about 6 hours all up with waiting for glue to dry etc.
bstott
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Joined: Wed Sep 19, 2012 5:28 am
Location: Pittsburgh, PA USA

Re: Board coils discussion

Post by bstott »

Tony or someone who has tested.
What are good uH values for a board and pcb coils, respectively? :?:

I bought a inductance (coil) testor kit and now would like to get all my coils set to a set value.

Thanks!
Tony
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Re: Board coils discussion

Post by Tony »

I did buy a couple of attinys to build a L meter but still haven't had a chance to do so. Tried measuring them using the scope and signal generator trick but the values came out higher than I think would be correct - about 20uH from what I remember. You had an early kit with a pre-wound coil - what does that read?.
bstott
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Joined: Wed Sep 19, 2012 5:28 am
Location: Pittsburgh, PA USA

Re: Board coils discussion

Post by bstott »

Yes, to test your coils would be the way to go - But, I did loose your one board coil amongst a number of others. A helper - helped. :o

Thanks for the 'duh' reminder. I do have the pcb coil to check. :)
AndrewB
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Joined: Sun Jan 27, 2013 1:48 am

Re: Board coils discussion

Post by AndrewB »

I measured 133 uH on the piece coils & 192 uH on the board coils. I added an extra turn to a board coil and came up with 200 uH. This was on an Agilent U1733C.

That seems pretty close to the theoretical value. There is a calculator here:

http://www.66pacific.com/calculators/coil_calc.aspx

Average diameter 3cm
Coil depth 0.2cm
46 or 55 turns
bstott
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Location: Pittsburgh, PA USA

Re: Board coils discussion

Post by bstott »

Thank you. :D
leedawg
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Joined: Mon Feb 11, 2013 8:42 am

Re: Board coils discussion

Post by leedawg »

So I do have a quick question. Before I bolt all these coils onto the board. Are they supposed to be bolted with the wings down on the component side so the coile is actually a little bit above the surface components. Or is is supposed to be bolted wings down onto the solder side of the board? I cant seem to find any pictures showing the board assembled with the coils on it. Thanks appreciate it guys. Winding one coil at a time.

Lee
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