Surf PI Pro

[sentella4d]

Hello Qiaozhi;
We'll I tell you the truth,I do not think the " unit has been assembled, tuned and tested for maximum performance.". Initially when i received the board,only the volume and sensitivity pots seem worked.If i moved the volume or sens pot ,i could control the threshold volume. But,although the components were soldered very well,the person who assembled the unit forgot to solder one of the cables of the threshold pot,it only came with two cables soldered,instead of the three.It took me more than a day to figure out why the detector could not control the threshold tone.It was missing the third cable to the board.After i soldered the pot correctly i could control the threshold,but it still would not detect any metal.

[Qiaozhi]

Have you thought about contacting the seller? According to the eBay listing: "This unit has been assembled, tuned and tested for maximum performance.".
Apparently all you need to do is connect the coil, and no tweaking of the trimmers is required.

[sentella4d]

Hello forum members;
My name is Angel, I am new to the forum.I bought this surf pro pi kit already assembled: http://www.ebay.com/itm/231202148661...84.m1497.l2649

I have wound the recommended coil; 21 turn, 9.1 inch, 24 gauge coated enamel wire, set up the offset to 0 volts and the r2 trimmer to 3.3k but the coil will not detect any metal.I have tried setting r2 to between 2.3k and 3.6k to no effect. I am using 4 feet of RG-58u to connect the coil to the board,and i am not close to nay metal.No matter what r2 setting all i get is a constant threshold sound,no metal detection.I am able to control the volume level and threshold with the pots,but the pulse delay and sensitivity pots seem to have no effect.

I measured the 5v and - 5v rails and i get +5.1 volts and -4.84 v.
I have tried t check for any solder bridges or loose welds but none were found.I have tried changing the component configuration according to these forum posts:

http://www.geotech1.com/forums/attachment.php?attachmentid=24310&d=1365551799

I also tried these suggested modifications:

http://www.geotech1.com/forums/attachment.php?attachmentid=24368&d=1365944910

.,I also tried a 125 mm id, 30 turn flat spiral coil wound with 24 gauge speaker wire as suggested but no change,just a constant threshold.
I have very limited electronics knowledge.No matter what I try it does not work,I have no oscilloscope I am stumped,I do not know what to do...Please Help!!!

Angel

[geoscash1]

http://pics.data.bg/categories/1/%D0...ochnyj_datchik

With this probe, will be more sensitive machine?

That looks like it would be a bear to wind up.. Are the 4 strands wrapping the outside separate from the inner windings or is that all one piece of wire,
looks like it might take quite a bit of time to wrap that up...

It would be nice to see someone do a video of winding one of these up or the other basket coil I have seen in here..

EDIT: Well, I see it is all one wrap now..my bad, should have known anyway....lol

[mohandes]

Looks pretty good.

hi can you teach me to this coil winding.
regards

[chemelec]

http://pics.data.bg/categories/1/%D0...ochnyj_datchik

With this probe, will be more sensitive machine?

Looks pretty good.

[farafero]

http://pics.data.bg/categories/1/%D0%BE%D0%B1%D1%89%D0%B8/1dca86be04586e9a2c781ee9e70c43df/korzinochnyj_datchik

With this probe, will be more sensitive machine?

[porkluvr]

Sorry, Harp. I realize that I did not really answer your question (I was actually hoping that would not matter if I showed you something simple but still workable) - but by the time I had worked out the details I figured I may as well share it.

Of course it makes a lot more sense for a battery monitor to have a "battery bad" LED come on suddenly, rather than having a "battery good" LED slowly fade away.

[mohandes]

I would like to throw out audio battery check, and make the check visually via LEDs.

I wonder, if I remove everything that is marked by a red line, or do I leave the green line, in order to the unit working normally?
Thanks!

good idea .
an you add led to circuit when detecting led on and when not detecting off.
regards

[Tepco]

If you have problem making\routing PCB traces, you can swap IC pins. 4066 chip contain 4 independent analog switches, 3 used in circuit. Each have one control input and two switch connections, marked U4 A,B,C,D. You can interchange them, also interchange switch outputs. For example if you change U4A (pins 13, input, and 1,2 outputs) with U4B, not used in circuit, (pins 5,4,3,) or U4C or D this will work. Also output pins are interchangeable within same section, for example pins 1,2 or 3,4 etc can be connected in any direction if this can simplify PCB layout. Same is for sections of U5 and U6, can be swapped.

[Harp]

thanks you for the quick reply!
You disrupted my "plans" ...

[Tepco]

You must keep this part of the circuit, audio wont work without it. Not just battery voltage test (this will actually work without IC), U4A is audio chopper, used to modulate U7A output with audio tone derived from U6D. Do not remove it.

[Harp]

I was a little clumsily expressed ... hard for me to find the right words, sorry.

Just want to know if I can this input of CD4066 (defined by a red/green line) disconnected from the rest of the circuit, and to continue to work normally?

low level indicator would later incorporated, something like this:

http://dmohankumar.wordpress.com/2012/10/19/low-battery-indicator-beginners-trial-10/

I need knowledge of technicians, because just draw tile, I stopped in this detail. I want it out, if it is not necessarily required for the normal functioning of the device.
So if this input 4066 is just to drive baterry check, then I would be happy to shut down, but asks you to confirm someone who knows, or who may be tested.

Thank you!

[porkluvr]

It would be a bad idea to power an LED through one section of the CD4066.

If you can kludge in one resistor, one transistor, and one capacitor, this should work. The capacitor is there to quash what otherwise would be a nasty spike.

You might want to use a different zener, and adjust the series resistor according to the lower limit of acceptable battery voltage. Even with the R30 being zero, the 1N755 would be useless with a 12V battery unless you wanted the LED going from full brightness to fully dim as the battery fell from 12V to just slightly lower than 11V.


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edit: I just realized that I used a model for a white LED... After replacing it with a RED LED model, everything still looked about the same except that you should increase R30 to about 200 ohms... to keep current below .03A

[Harp]

LED low batery indicator

I would like to throw out audio battery check, and make the check visually via LEDs.

I wonder, if I remove everything that is marked by a red line, or do I leave the green line, in order to the unit working normally?
Thanks!