Surf Pi Post assembly checks?

[DOOLEY]

Lefizz,when testing keep piezo away from coil,not only will detector pick it up but magnetic field will make it sound,its not that a piezo is special,any thin flat piece of metal will also make a sound.for testing purposes i try to get coil hanging from ceilng 3 ft away from anything.oh,and watch out for the plauge of the 1hz clock signal from wall clocks with the coil drive mechanism.

[golfnut]

My PC is normally on while I experiment - it causes falses whether its ON or Standby.

My Tv can cause trouble, monitors, cellphones, nails in floor boards, water pipes, electrical wires - U name it.

Steve

[Lefizz]

Used 8 bateries in the packs and a wire to short out the remaining missing AA's

Ok i moved the whole lot somewhere else and it works, not much sensitivity yet but its works more or less. I have now heard the mention 1hz clock signals, goes crazy near a lighting socket. Very interesting.

So tuning without a scope is a matter of dialling up and down the delay pot.

What sort of distance should i expect with say a 1 euro coin?

[golfnut]

You may of asked that before you bought the kit

[homefire]

Back track The post it's in there a few places.

[silverdog]

Used 8 bateries in the packs and a wire to short out the remaining missing AA's

Ok i moved the whole lot somewhere else and it works, not much sensitivity yet but its works more or less. I have now heard the mention 1hz clock signals, goes crazy near a lighting socket. Very interesting.

So tuning without a scope is a matter of dialling up and down the delay pot.

What sort of distance should i expect with say a 1 euro coin?

Indoors, roughly the diameter of your coil would be a good start

The pots are 25 turn but still quite sensitive when you get to the delay adjustement - when you can detect iron/steel adjust a quarter turn at a time until you can detect gold

[Lefizz]

Hi again,

with the coil I built from some pickup wire i can get around 6 inch on a 1 euro coin and about 2 inches on a gold ring ( its white gold i am sure that doesnt matter does it?) I guess i will have to experiment with coils a bit. Still I am sure that half the fun and when I get my LCR meter it will be a lot easier.

Regards

Phil

[Lefizz]

Hi,

Just to say that after trying to tune with headphones rather than the buzzer, jezz what a difference, I can get a pretty solid signal around 8inches on a 20cm coil which sounds about right doesnt it. I can pick up my girlfriends smallish gold engadment ring (I'm skint) at around 5 inches which is better than the only other detector I have here. A C-Scope 770D from the earl 80s. So I am slightly better than 30 year old tech yea-ha.

If i wanted to tune up the detector more what should i do. Is my coil a bit small?

Generally successful day though and thanks a lot for all the advice.

The 28awg enammelled wire coil seems better to me than the 0.5 mm pickup wire.

[Comp]

Hi,

Just to say that after trying to tune with headphones rather than the buzzer, jezz what a difference, I can get a pretty solid signal around 8inches on a 20cm coil which sounds about right doesnt it. I can pick up my girlfriends smallish gold engadment ring (I'm skint) at around 5 inches which is better than the only other detector I have here. A C-Scope 770D from the earl 80s. So I am slightly better than 30 year old tech yea-ha.

If i wanted to tune up the detector more what should i do. Is my coil a bit small?

Generally successful day though and thanks a lot for all the advice.

The 28awg enammelled wire coil seems better to me than the 0.5 mm pickup wire.

There you go!!!!!! Well done!!!! 2 weeks ago, you were going to bin/ put a hammer through it!!!!!!! A bigger coil will get you a tad more depth, if you have a scope you can monitor the pre amp output for any ringing, and 'tweak' the damping resistor for best detection,.....

You should get depth equal to your coil diameter comfortably, and a bit more with some work,...... Well done, and Happy Hunting!!!!!!!

Cheers, Fred

[Lefizz]

Thanks Fred,

Got to say I am quite happy with it at the moment, been an emotional roller coster up n down. Just got to think of a way to package the unit. i have seem people build coils into bent pipe joined together, i have to say that doing that is quite impressive if you can still get the required inductance.

What is the sensible limit then if coil diameter is close to the depth you get? 12 inches?

[Comp]

Well, I am in the same position as you, at the moment!!! I get same sort of depth, with a 20mm coil. I have a day off work tomorrow, and I have some 27cm diameter coil shells, so hope to wind a bigger coil, and to have a play with some wire and resistors!!!!

Some posters on here talk of 30 to 35 or 40cm depth detects,.. I can get that with a soup/bean tin, but not with a coin,.... but I will keep playing, will post any new results!!

Cheers, glad you are having some positive results, Fred

[homefire]

Well, I am in the same position as you, at the moment!!! I get same sort of depth, with a 20mm coil. I have a day off work tomorrow, and I have some 27cm diameter coil shells, so hope to wind a bigger coil, and to have a play with some wire and resistors!!!!

Some posters on here talk of 30 to 35 or 40cm depth detects,.. I can get that with a soup/bean tin, but not with a coin,.... but I will keep playing, will post any new results!!

Cheers, glad you are having some positive results, Fred

Did you see the Issue with R18 and R22?

[Comp]

Did you see the Issue with R18 and R22?

Yep, twas me that found it, if you recall!!!! (Took me 2 weeks to find it, though, I am ashamed to admit!!!)

I have found that different coils cause 'hiccups' in the delay setting, I'm sure I will hit an optimum coil inductance soon,...... looking around 400 to 500 microhenrys at the mo...........

LOL!!! Cheers, Fred

[homefire]

OOOPS sory I missed that. Sorta under the times the past few weeks.

I know I commented on it but having problems remembering names.

[Lefizz]

Well Fred, let me know how you get on. Love to hear your results so keep us updated.
I might have a play tomorrow night as well cos the missus is out, I am going to try something BIG and see how it does. For me it all about finding big enough things yo wrap around