Surf Pi Build + inbuilt pinpointer

[pberrett]

These are various coils I have made and I will choose whichever works best once I get the circuit up and running again.

I made a spiral coil using twin speaker cable. It worked pretty well but I found it was a bit heavy so I have reduced it to a single cable and rewound it. We'll see if it still works. Next is a coil wound with 21 turns of 24 awg copper wire. It is wrapped in aluminium foil and then taped over. I'll see if this works better and also warp it into an oval shape which I'm told gives better depth.

You can see the prewound coil I used to test the pinpointer idea but I have since wound several turns of 24 awg copper wire around a cardboard tube which in turn is wound around a ferrite rod. We'll see how that performs as well

 

[pberrett]

The almost completed circuit board with a number of parts now replaced. I put an electrolytic capacitor (the wrong way round and something got fried. It also fried my irf 9640 mosfet.I've replaced most of the components up that end of the board and I'm getting proper power +5v and -5v to the chips ok now. I'm still waiting on a replacement irf 9640. In the meantime I have the fried mosfet out and I've run the board on power. Nothing is heating up so so far so good. It is just a question of how the new Mosfet behaves after I install it.

 

[pberrett]

The rear of the main unit with connections to the coil and pinpointer.

 

[pberrett]

I'm close to finishing my build but have a couple of other questions. I've been looking around for a suitable pole to mount the unit on but most of the ones i have seen which would be good (eg mops) have metal poles. Some are really good and are extendable. Would a metal pole be a problem and interfere with the unit or does it not matter because it is not moving relative to the coil? Similarly the joint that connects the pole to the coil housing will probably need a metal bolt. Is this a problem?

Also I need to find a waterproof container to hold my coil. Any ideas?

Finally what is the best depth anyone has gotten with a stock (unmodified) Surf Pi 1.2?

 

[pberrett]

Also a question for Gcause... When using the Baracuda in regular sand how did the depth compare to the Surf Pi 1.2?

 

[Drbean]

OK mate what I would sugstis converting to double d more stable
If you want I can post how to do just remove 1 k from pin 3to MOSFET
and solder RX wire to free end of 1 k this will sepperate tax from RX
and allow you to run did coil and then you solder in 5 pin audio connector
You then can run a coil tech or nugget finder coil .no need to reinvent
the wheel bud .I used a crutch and and the mine lab shaft went straight in.
No don't put metl near pin go to hardware store and find a nylon bolt and nut
to hold coil on .they are a good unit though I used kit from states on eBay
called sm pi surf has more adjustable external pots and is square board.
Has volume , delay , sesativity , and threshold and is easeier to build.Dr

 

[joe]

I'm close to finishing my build but have a couple of other questions. I've been looking around for a suitable pole to mount the unit on but most of the ones i have seen which would be good (eg mops) have metal poles. Some are really good and are extendable. Would a metal pole be a problem and interfere with the unit or does it not matter because it is not moving relative to the coil? Similarly the joint that connects the pole to the coil housing will probably need a metal bolt. Is this a problem?

Also I need to find a waterproof container to hold my coil. Any ideas?

Finally what is the best depth anyone has gotten with a stock (unmodified) Surf Pi 1.2?

Here is a pic I found for ya, PVC good luck mate

 

[pberrett]

Hi again everyone

I finished my metal detector & pinpointer and you can see the build in this episode of Amateurlogic. The segment starts at about the 40 minute mark.

https://www.youtube.com/watch?v=KG8kowLOfYw

cheers Peter