Surf PI Pro

[igull]

Yet another Surf PI

Hi All

Just finished my surf pi from a silverdog pcb. Nice pcb, very well made.
My only issue was finding a control box to suit - 170mm is just on the long side for most instrument boxes - they end up too wide as a result.
However, there was probably a really good practical reason for making it long and thin (there's an opening for a joke there ) I'm just using it for the wet beach/mud - this one is actually going to a friend who is currently 'Minelabless' after the PSU board on his explorer died.
I laser cut a coil former from 3 layers of 2mm MDF with 6mm acrylic lugs - it's really surprisingly strong. I'd like to cut another set as a plug and vacform a cover from ABS next time - maybe use injected urethane foam for lightness instead of epoxy - I have all the kit from making making glider fuselages, it's just lazinesss to get started again
Machine is very light, just what I need really.
Looking forward to trying it out this weekend.
BTW, any mileage in making a huge coil for this beast, I haven't seen any mention in the forum?
Apologies for the dodgy iPhone pic.
Cheers
Neil

[ApBerg]

igull:
However, there was probably a really good practical reason for making it long and thin (there's an opening for a joke there )


Well I go for the joke..... you can replace the led for a buzzer motor.. you see also the reason for the long and thin board..


http://www.geotech1.com/forums/showt...highlight=surf

[Qiaozhi]

igull:
However, there was probably a really good practical reason for making it long and thin (there's an opening for a joke there )


Well I go for the joke..... you can replace the led for a buzzer motor.. you see also the reason for the long and thin board..


http://www.geotech1.com/forums/showt...highlight=surf

Aha! ... so you're suggesting that it could be used as a probe.

[UFO]

Does your ***** need to be metal?

Perhaps the erratic behavior of the Blisstool would be better suited for such conversions.

[bernte_one]

hello

yesterday i made a simple coil of 18 windings
of 0,5mm insulated single core copper wire
L 280microH R 2,7 Ohm
very simple and works great for surf pi pro with no threshold sound i get 32cm for 2 euro coin
at this detector you can adjust a lot
i think the gain ist the best function on it

its easy to build so i can tell all here to give it a try
think its one of the top 5 for the beginners

i plan a dual field but not sure wich characteristics it should have
a one with a too high L and R seems not to be good for short puls delay
and a type with low L (micro Henry 150-200outer 150-200 inner) seems not to be strong enough to reach 40cm ?

but i will try and tell you

regards

[golfnut]

Hi, did you sheild or no sheild?

What Diameter was your coil?


I find the delay pot sweeps thru the available range very quickly - did you find?



Prepare for digging a lot!


I made a coil approx 100mm dia from 20T of 0.3 enamelled and its fine also.

S

[6666]

bernte_one

While I have not tired it yet, somebody on the forum suggested a DF coil like this to try

wire about 24 gauge multi strand , 11.5 inch 16t, 6 inch 19t.

They said it was a killer coil.

[bernte_one]

hello

@golfnut
coil is unshielded with d shape the straight line has 25cm lenght and the bow over the line has a hight of 22cm it is fittet into a pe pipe

what you see at the dalay pot is the same i see there but also on offset
mine wokrs best when offset ist set around 90% and delay under 25%
but it is different from coil to coil so you have the choice the change coil while hunting

the best thing is that you can hear the different tones of the targets long soft till short and hard

@6666
thanks for coil datas i will try when i get new litz wire i spend my last of 0,5mm (24awg) to build my planar coils


regards, nice evening

[bernte_one]

led output

hello

can i place a single(white, blue or green) 5mm led parallel to audio out
so that i can see when target is detected when i have headphone disconnected
or would the led damage the audio supply on pcb
or take to much current/ voltage ?

i think it should make no problems but maybe one of you see some trouble that could appear?

regards

[igull]

No problem with an LED, just need a resistor to limit the current - 470R or so.
Bear in mind that the LED wont be that bright due to the signal being a high pitched square wave (duty cycle will I guess be 50%).
You could easily change the code to send the pin hi instead of putting out a sound (or low depending on which rail you connect the LED to) - a simple thing to change on picaxe. Adding items like a small FET to drive a vibrator are also easy.
Cheers
Neil

[TH Jim]

The duty cycle on the audio is much less than 50% - more like 5% as it is being taken from a gate timing pulse. see the surf pi patent.

[igull]

Oops

I posted in the wrong section, I thought the question was directed toward my picaxe probe, I just received an email and replied without looking - my apologies :-)))))
Make sure my other brain cell is connected next time

Cheers

Neil

[yhl]

The use of three cell phone batteries in series./Cable is a coil twisted pair.

The use of three cell phone batteries in series./Cable is a coil twisted pair.

[yhl]

good

good coil

[TH Jim]

Hi yhl,

Interesting coil. Neatly constructed. Could you tell us more please.

What is the inductance of this coil?
What is the minimum delay it will sample at?
What is your detection depth on coins and rings?

Regards, Jim