IDX-PRO+VDI

[sdesic]

I just rediscovered a spray paint that contains graphite to make easy work of shielding.
Here's a link to Tractor Supply To buy some;

http://www.tractorsupply.com/en/store/ez-slide-graphite-based-coating-12-oz-aerosol

And here's the thread I found it in;

http://www.geotech1.com/forums/showt...nductive-paint

this is European version

http://www.conrad.com/ce/en/product/813826/GRAPHITE-33200-ML

[Silver Dollar]

I just rediscovered a spray paint that contains graphite to make easy work of shielding.
Here's a link to Tractor Supply To buy some;

http://www.tractorsupply.com/en/store/ez-slide-graphite-based-coating-12-oz-aerosol

And here's the thread I found it in;

http://www.geotech1.com/forums/showthread.php?11691-conductive-paint

[jlsilicon]

For reference, here is an example to show this X to Y curve :

https://www.youtube.com/watch?v=m9DuMekVwic

And, described a little here:

http://www.geotech1.com/forums/showthread.php?18958-Arduino-based-VDI!&highlight=youtube

[golfnut]

I just realized a problem in the PicBasic or Arduino X/Y Readings Software :

The X/Y Map is an Elipse (squished circle) angled by the Metal's X and R, the Reactive and Resistive Components.
So, a Sample of Readings over a Time Frame will vary around the Elipse.
These readings often will not follow the Simple Division Equation used in the Software.
Because, it is NOT a SIMPLE LINE ...
Especially on the ends of the Elipse.

This would explain the range of readings that I get.

I saw a good Oscilliscope Vid and Photos somewhere ...

Your right, the largest values in your array would be though, max X and max R for the tan-1 function.

You notice on commercial units sometimes it takes several passes to give a good ID and even then the reading fluctuates

[sdesic]

i used a small square of copper tape(4mm square), i stuck this on the card and soldered the fine tag wire to it, then i coated the card with graphite making sure i put a nice dollop on the soldered spot.
for the bottom piece of card i did the same thing added a small square and put a tag wire on it, if you find the right spot to place the tag you only need a small length of fine wire to join the two, the shield braid solders to this, the graphite i use is graphite powder mixed with clear acrylic lacquer, to sat dave uk's recipe, the only difference between his and my recipe is he uses polyurethane varnish, i am violently allergic to polyurethane paints so substituted acrylic lacquer.
i did try spray on graphite but i think its a- too expensive, b- too loose it needs a fixing agent, c- makes a bloody mess as it just comes back off.
with a nice coat the solvent soaks into the card (then dries) leaving a solid carbonised faraday shield which works very well for me.

Pictures of White's coil bottom part



pictures are worth 1000 words ?

[sinclairuser]

How do you connect your tap wire to the card. I have tried just tape and it works well but don't think long term reliability would be good. Also tried graphite mixed with PVA glue into something like toothpaste this is conductive but you can pull the wire straight off as it dries as a powder.

i used a small square of copper tape(4mm square), i stuck this on the card and soldered the fine tag wire to it, then i coated the card with graphite making sure i put a nice dollop on the soldered spot.
for the bottom piece of card i did the same thing added a small square and put a tag wire on it, if you find the right spot to place the tag you only need a small length of fine wire to join the two, the shield braid solders to this, the graphite i use is graphite powder mixed with clear acrylic lacquer, to sat dave uk's recipe, the only difference between his and my recipe is he uses polyurethane varnish, i am violently allergic to polyurethane paints so substituted acrylic lacquer.
i did try spray on graphite but i think its a- too expensive, b- too loose it needs a fixing agent, c- makes a bloody mess as it just comes back off.
with a nice coat the solvent soaks into the card (then dries) leaving a solid carbonised faraday shield which works very well for me.

[der_fisherman]

Hack Lugatek VDI

Part1

https://www.youtube.com/watch?v=2So4QTbI5Ls&feature=youtu.be

Part2

https://www.youtube.com/watch?v=3s7DWjWDVLI

Part3
https://www.youtube.com/watch?v=kil9McoVWis

I watched all three videos, I learnt nothing. What was the point?

Andy

[Koala]

How do you connect your tap wire to the card. I have tried just tape and it works well but don't think long term reliability would be good. Also tried graphite mixed with PVA glue into something like toothpaste this is conductive but you can pull the wire straight off as it dries as a powder.

[sinclairuser]

See your problem not a good housing for this solution


Does not have to be close to the windings you could just stick the circle of cardboard to the top and bottom just to prove it works.


Would have to work out some type of waterproofing for a long term solution


I have the same problem with packaging on one of my coils. Can't figure out why wrapping micopore tap around the coil and covering with carbon does not work as well as the cardboard. Think it might be the tiny creases that cause a none smooth coating. Need to try a couple more experiments.

Haven't tried covering the micropore before wrapping around the coil to give a more even coating
Haven't tried wrapping a single layer around the outside of the coil instead of spiraling it around
Haven't tried spacing it away from the windings


You could try the graphite spray directly to the housing.


Tried and failed with micropore tape spiraled around each winding and then covered in graphite
Tried and failed with one layer of PVC tape then space blanket then PVC
Tried and failed with two layers of PVC tape then space blanket then two layers PVC
Tried and failed with tap wire under the space blanket conductive side down
Tried and failed with tap wire above the space blanket conductive side up
Tried with the shield connected at the RX GND at the coil
Tried with the shield connected only at the box end
Tried with the coil connector shielded and none shielded
Coil covered with space blanket is worse than no shield at all
Tried some with a second TX and RX windings same results.
Gave up with space blanket
Can't find out why it does not work for me as others have had success using the space blanket.

Card worked straight out of the box. Not just a fluke as I have tried again same result. Still not quite as good as my factory coil but pretty good.

Hi koala, been reading your posts in this thread, and what you say is spot on, i could not get space blanket to work either, a simple shield made from stiff paper or fine card coated in graphite worked every time for me.
so now i just make a card faraday shield and coat it with graphite, and its surprising how little graphite makes a useable shield.

[mikipn]

Hack Lugatek VDI

Part1

https://www.youtube.com/watch?v=2So4QTbI5Ls&feature=youtu.be

Part2

https://www.youtube.com/watch?v=3s7DWjWDVLI

Part3

https://www.youtube.com/watch?v=kil9McoVWis

[jlsilicon]

I just realized a problem in the PicBasic or Arduino X/Y Readings Software :

The X/Y Map is an Elipse (squished circle) angled by the Metal's X and R, the Reactive and Resistive Components.
So, a Sample of Readings over a Time Frame will vary around the Elipse.
These readings often will not follow the Simple Division Equation used in the Software.
Because, it is NOT a SIMPLE LINE ...
Especially on the ends of the Elipse.

This would explain the range of readings that I get.

I saw a good Oscilliscope Vid and Photos somewhere ...

[sdesic]

Koala,

Wow you have done it all
Review of shielding in full.
Can you post picture of your finished coil.
You have used graphit spray and cardboard - from top and bottom.

We should have sticky posts here for latest schematics and PCBs.
I think this is latest ?
Geotech_VDI.rar

[Koala]

How do you do you cut card board to fit coil enclosure ?

My coils are in this shape ...
[ATTACH]30895[/ATTACH]

You have cover under coil ?

See your problem not a good housing for this solution


Does not have to be close to the windings you could just stick the circle of cardboard to the top and bottom just to prove it works.


Would have to work out some type of waterproofing for a long term solution


I have the same problem with packaging on one of my coils. Can't figure out why wrapping micopore tap around the coil and covering with carbon does not work as well as the cardboard. Think it might be the tiny creases that cause a none smooth coating. Need to try a couple more experiments.

Haven't tried covering the micropore before wrapping around the coil to give a more even coating
Haven't tried wrapping a single layer around the outside of the coil instead of spiraling it around
Haven't tried spacing it away from the windings


You could try the graphite spray directly to the housing.


Tried and failed with micropore tape spiraled around each winding and then covered in graphite
Tried and failed with one layer of PVC tape then space blanket then PVC
Tried and failed with two layers of PVC tape then space blanket then two layers PVC
Tried and failed with tap wire under the space blanket conductive side down
Tried and failed with tap wire above the space blanket conductive side up
Tried with the shield connected at the RX GND at the coil
Tried with the shield connected only at the box end
Tried with the coil connector shielded and none shielded
Coil covered with space blanket is worse than no shield at all
Tried some with a second TX and RX windings same results.
Gave up with space blanket
Can't find out why it does not work for me as others have had success using the space blanket.

Card worked straight out of the box. Not just a fluke as I have tried again same result. Still not quite as good as my factory coil but pretty good.

[sdesic]

How do you do you cut card board to fit coil enclosure ?

My coils are in this shape ...


You have cover under coil ?

[Koala]

I will need to aquire new wire then.
Shielding for concentric coil is simpler ... what can be done for DD ?
I have small beeps on ends of swing - maybe shield and can be fact that I did not use resin to cover it.

My coils are DD
Circle of card with carbon on them under and over both the TX and RX
Must of tried over ten times with a space blanket with two sets of windings can not get it to work properly I must be doing something stupid card works fine nice and simple just rubbed a carbon battery on it even a small circle under the coil had more success than I had with the blanket.