Whites Surf PI schematic

[Old cart]

i don't have an oscilloscope
My question is....what part of the circuit should be responsible for this?

Tita, your surf seems to be working normally. It probably is not detecting the chain well because it is either not sampling early enough or the coil will not allow early enough sampling or the coil is not properly damped, or all of the above.
Unfortunately, this will be difficult to determine without an oscilloscope and the knowledge to use it.

[Old cart]

Here's a Schematic I drew in Express for Old Cart and others to be able to edit;

Thank you. I don't have an (un) zipper here so I will look at it later. Did you draw this from scratch?

[Old cart]

it seems as surf pi but only power supply is different. Does it work according to you?

Thanks but this one is modified. I has changes to at least the power supply and the transmit driver circuit.

[ashkelon]

different surf pi

it seems as surf pi but only power supply is different. Does it work according to you?

[Tita]

i don't have an oscilloscope
My question is....what part of the circuit should be responsible for this?

[FatBob]

Here's a Schematic I drew in Express for Old Cart and others to be able to edit;

[daverave]

yes the surf pi should detect your 7mm gold chain...not sure what depth you would expect on that as ive never tested with 7mm chain...you really need a scope to see whats going on in the circuit...ive made 4 surf pi's and never really had much problem with them.

[Tita]

i don't think that it's so thin.......it has about 7 mm

https://www.google.ro/search?q=gold+chain&espv=2&biw=1360&bih=663&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiGyIvXgZPMAhWEQBQKHd6fDnsQsAQIHw#imgrc=lOfHZc92fFThoM%3A

[daverave]

if its a thin gold chain your asking a lot for a unmodified surf pi to detect that....some commercial pulse detectors cannot detect thin gold chains...you would need a fast coil to give you about 8-10 uS delay and maybe a higher frequency coil drive around 3 khz....try a US nickle coin and that will be a good test as a low conductive item.

[Old cart]

I am writing a build guide for the Surf PI V1.2 as sold by Silverdog. It is about half way done. I plan on adding a complete schematic to the guide. I have the schematic off of Silverdogs site but it is a PDF which I can not edit. It could use editing for clarity. Does anyone have an editable version of that? I think the original was down by Ap berg.

I am writing the guide based on the Minipulse so if you have any ideas or thoughts pass them on.
thank you.

[Old cart]

Can someone tell me what is current consumption of the surfmaster PI?

about 100 mA?

[Tita]

Can someone tell me what is current consumption of the surfmaster PI?

[Koala]

Yes i adjust them correctly and it's still not detecting my gold chain......it's detecting a coin at 20-23 cm ..........
I don't understand why at least a weak sound at 1 cm...but nothing).

Sounds normal for a ladies pendant chain. Sometimes the clasp is the only bit that's detectable.

[Old cart]

Yes i adjust them correctly and it's still not detecting my gold chain......it's detecting a coin at 20-23 cm ..........
I don't understand why at least a weak sound at 1 cm...but nothing).

How fine is your gold chain? If it is very fine it behaves as if it is a bunch of individual targets. This may be completely normal.
Is the coil shielded? If so with what and does it form a complete loop?

Try the following steps. After each each step carefully adjust the threshold for a minimum audible tone.
Make sure the coil is at least 3 feet from any large metal objects.
If you have US nickel use that as test target. If not try the pull tab off a soda or beer can. Lacking those try a 1 inch square of tin foil. Any test target must be moved quickly to get maximum depth. Experiment to find out the best speed.

1. Set the delay pot to minimum resistance which is minimum delay. Test
2. Double check the board against the board layout to make sure there are no shorts between traces. The board does not look like it was cleanly etched. If there are shorts cut the trace with a sharp knife like an exacto knife. Test
3. Test and report the battery voltage after the detector has been running at least 1 minute.

[Tita]

Yes i adjust them correctly and it's still not detecting my gold chain......it's detecting a coin at 20-23 cm ..........
I don't understand why at least a weak sound at 1 cm...but nothing).