Minipulse Plus Rev My time has come!

[mushaba]

Went to my best friends router and engraved the coil patern 10mm deep and wide (The coil measures about 6mm OD).He blew my mind with these tinny wedges made with his laser cutter also from wood to keep coil parallel to the form sides so there is room for epoxy to fill it all the way through!Im worried about if the epoxied coil easilly will "go" out of the form.

[green]

I wonder if it's possible to use the MPP with a coil 1m x 1m square like Delta pulse,the damping procedure will be the same I believe Did anyone try it?

Been following your thread. Been thinking of making a coil for larger targets with some AWG19 enamel coated wire I have. Including a chart I posted awhile back comparing signal strength vs distance with three different diameter coils assuming everything else remained the same. Wondering what needs to be done to make the MPP a good large target detector(learning exercise). What targets are you looking for? What is the largest coil you would like to use?

[godigit1]

The wedges are actually ply wood, even the more impressive you coould not have done that with a router.
How do you plan on sealing your MDf. If I may I would suggest a liquid thin epoxy Or a wood hardener used for restoring rotted wood.
Pc Petrifier would work and is not that expensive. I have a wood shell and thats what I was going to use and then clear coat but mine is maple ply wood so I was going to make a woody style coil.
This is a way you can do a easy form for that style of coil and that is to use a embrodrary hoop glue on 1/8 ply and you have a form for a laminate router.

[mushaba]

Been following your thread. Been thinking of making a coil for larger targets with some AWG19 enamel coated wire I have. Including a chart I posted awhile back comparing signal strength vs distance with three different diameter coils assuming everything else remained the same. Wondering what needs to be done to make the MPP a good large target detector(learning exercise).What targets are you looking for? What is the largest coil you would like to use?

Hello green.Generally in Europe hunters go for stashes of rebels and nazi WW2 gold.Usually they putted the gold in metal ammunition boxes,in cans of food and stuff.The searching will take place mostly at mountains ..My plan is instead of looking for gold directly to look for metal but not for small ones (nail,pultabs etc)..Since PI detectors cant reject iron i was thinking , as i said to George some posts ago , to go bigger on coil so i will have depth and reject the small items.Thats why i was thinking to try a 1m x 1m square coil.

Tested the coil i made today with the MPP and noticed the following things (i didnt remove the coil from the MDF waiting for the epoxy to harden):

1) Coil gained me a little detection range-distance on large items and lost a little at small.As it should.But in close proximity it still detects small items.For example with the 3dss an gold coin (22mm OD) was detected at 27-30cm) with this coil at 18-20cm.
2) Larger coil should be more "slow".Damped around 2k it has a very nice curve and can sample at 9us.
3) Watching the preamp output i was getting some noise that had period,moments it had a normal curve about 800mV and at other moments the noise went up to 2V.Some wird interference i cant explain
4) Working too long with a coil at 500 pps and Tx pulse at 300us gave me a headache..

[godigit1]

Even can use them for the coil form itself. They are cheap in second hand stores and and they come pretty big.

[mushaba]

The wedges are actually ply wood, even the more impressive you coould not have done that with a router.
How do you plan on sealing your MDf. If I may I would suggest a liquid thin epoxy Or a wood hardener used for restoring rotted wood.
Pc Petrifier would work and is not that expensive. I have a wood shell and thats what I was going to use and then clear coat but mine is maple ply wood so I was going to make a woody style coil.
This is a way you can do a easy form for that style of coil and that is to use a embrodrary hoop glue on 1/8 ply and you have a form for a laminate router.
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Hello godigit1 i potted it with epoxy hust to keep it steady and test it.If it works as i want i will vacuum form a coil housing..Also i thought a mix of wood glue fine wood dust and some varnish instead of epoxy

[mushaba]

Forgot to mention that i think 3dss or spider coils are much easier and robust than the simple bundle monos...

[godigit1]

This is true but require a thicker housing. Cool I like the vacumm forming and the way you chose to do it by putting the coil in a perminate form Good Idea!! I wouldnt use wood glue who knows what the dialectric properties really are.
I found a product called super corona dope and just had a idea for coils shielding using you new forming process.
So
1 make your ply form route in your channel.
2 vaccum your housing remove it.
Lay a loose wound bundle into your channel and I mean with no wrapping or even just rool it into the channel using a little peice of foam to lock each loop as you do it.
Then the super corona dope that is very thin would lock the coil into place. now you have primairilly air as your insulator A peice of cloth tape goes over the channel, the whole form is spayed with carbon paint and attached to ground then you just glue it into you final shell.
I know you are past that but just riffing on it a bit.
Best.

[mushaba]

This is true but require a thicker housing.

My fastest 3dss i potted in a flower pot bawl,it came near to 800 gr too heavy for its size...

Cool I like the vacumm forming and the way you chose to do it by putting the coil in a perminate form Good Idea!!

My best friend is a carpenter (the guy who has the laser cutter and the wood router i build for him for wood engraving and cutting 2.5m x 1.4m) We made a simple table with 5mm holes..We use 2 vacuum cleaner (household) and the forming looks awesome,we dont use extra vacum tank with compressor some other guys on the internet use (its best but we didnt try it) because we use 2mm PE or PP and it comes out real good..We made tank side covers for a Yamaha DT200R we restored!

I wouldnt use wood glue who knows what the dialectric properties really are.

True that it didnt cross my mind..In fact ive just removed the casting from MDF and it has a little better range..

I found a product called super corona dope and just had a idea for coils shielding using you new forming process.
So
1 make your ply form route in your channel.
2 vaccum your housing remove it.
Lay a loose wound bundle into your channel and I mean with no wrapping or even just rool it into the channel using a little peice of foam to lock each loop as you do it.
Then the super corona dope that is very thin would lock the coil into place. now you have primairilly air as your insulator A peice of cloth tape goes over the channel, the whole form is spayed with carbon paint and attached to ground then you just glue it into you final shell.
I know you are past that but just riffing on it a bit.
Best.

Thanks,im feeling i have long way before i will get to the point i will have my coils shielded..

Today arrived my CrossBow pcbs i ordered from jlcpcb,cant wait to build one..Should i try the Delta Pulse build first??

[godigit1]

I have not searched those detecors So Other members would bebetter to answer that.
But I wanted to add a thought on detector usage and a way of discing out small iron without desensitizing your coil. That is to simply raise your coil off the ground. If it is small shallow iron it will dissapear shortly after you raise the coil and large items will remain.
In prospecting we use the method just the opposite to disc out large Iron.

[godigit1]

Keep thinking about this form excellent for underwater. Very little air intrapment.

[mushaba]

Made another coil 20cm OD with 0.4mm double enameld coil wire.It damped at 820 ohms but I noticed scope reading on coil hot lead voltage went at 300v,I removed the 5 ohms resistor I had in series at the tx side and the damping changed..also noticed higher frequency have better detection range than lower freqs..Also read somewhere that an exceed Tx pulse could "overload" the ground we try to read from .(I don't know how to express it)..Almost finished my Crossbow,I'm out of 79L05 but I noticed some parts I didn't use from diydetectors kit had other value written than it's real value.Just hope that rev-c got from area51 are working..

[godigit1]

Made another coil 20cm OD with 0.4mm double enameld coil wire.It damped at 820 ohms but I noticed scope reading on coil hot lead voltage went at 300v,I removed the 5 ohms resistor I had in series at the tx side and the damping changed..also noticed higher frequency have better detection range than lower freqs..Also read somewhere that an exceed Tx pulse could "overload" the ground we try to read from .(I don't know how to express it)..Almost finished my Crossbow,I'm out of 79L05 but I noticed some parts I didn't use from diydetectors kit had other value written than it's real value.Just hope that rev-c got from area51 are working..



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Ive explained things that way kinda when running a VLF detector.
ITs Like Adding a fog to our vision more minerals become brighter. On a car you turn on the fog lights a different spectrum. On a High Frequency VLF
you turn down the gain sure you loose some depth but you gain the ability to see better.
The crossbow board looks good Im going to have to look at it more . Kinda interested in the TDX3 that DOOLEY deisgned though, I have a geo barra and chance to do but might shoot for a TDx first . Its a good example of less current to the coil and good performance wonedrful audio.
Soo many projects.

[mushaba]

Ive explained things that way kinda when running a VLF detector.
ITs Like Adding a fog to our vision more minerals become brighter. On a car you turn on the fog lights a different spectrum. On a High Frequency VLF
you turn down the gain sure you loose some depth but you gain the ability to see better.
The crossbow board looks good Im going to have to look at it more . Kinda interested in the TDX3 that DOOLEY deisgned though, I have a geo barra and chance to do but might shoot for a TDx first . Its a good example of less current to the coil and good performance wonedrful audio.
Soo many projects.

Exactly!A VLF should be on our arsenal and truth to be said from the few things I understood discrimination only with VLF.Is TGSL an easy build?Want also to build a PI with mcu,leaning to 2nd chance..After the CB I will try the Delta pulse,I think it's more suitable to the kind of detection I will try but there are no guides about calibrations..Having also a Svens Mirage board I'm gonna try.I need to learn more more about coils,about the part of receiving signal we try to convert to sound and how targets,ferous non ferrous (and other attribuutes of metals) behave on the above signal..

[mushaba]

Allmost finished the CrossBow (waiting for 5-pole connector for coil and the charging connector) and im really excited!!My first plan was to mount the detector as my MPP right down at the handle but i decided to mount on my belt via a belt clip since i dont have a proper mounting,there are lots of out there but they are pricy since a lot of custom fees and duty taxes are inolved,the housing is medium to large but managed to fit all parts in.I have to say its VCO audio is magical,nice and steady ticking adjustable as it has to be,little annoying on headphones because its too "mid-bass" for my hearing taste..A worry i have is the batteries (3x18650) is very close to PCB and somewhere i read something about 18650 and interferance.Also i will have to see the charging circuit because the original CB had NiMH battery pack.The Tx pulse is very steady (both pulse duration and frequency) and precisely adjustable.
I've also posted on area51 to hear from other guys built the CB and asking if there are some points to look after but i think the forum is nearly dead (no replies except Sven for a long time)..