Whites Surf PI schematic

[dfbowers]

Hello!

Do you think I can do away with the two CD4066s? Because I am not looking at the discrimination bit of the metal detector.

If so, is it possible to replace them with wires only? (And the input to the op amp would the same, right? =\)

Please advise, thank you.

No, you cannot do away with the CD4066 IC. It is not used for disc but is used as a gate to sample the decay curve.

[homefire]

Like stated, NOPE!

The signal would be meaningless. The signal has to be in the slice of time that reflects the target response.

[chocochips]

Like stated, NOPE!

The signal would be meaningless. The signal has to be in the slice of time that reflects the target response.

No, you cannot do away with the CD4066 IC. It is not used for disc but is used as a gate to sample the decay curve.

Oh my, does it mean I would have to build the whole chunk?

I have got not much time left for this project so I need to find a shortcut

How about linking the wire from Q1's emitter to the switches?

I'd imagine the Schmitt Triggers are made to close the switches when Q1's emitter goes to 12V (which is when the timers output goes to 0V) after the series inverting outputs.



Thanks again guys!

[chocochips]

update!

I managed to get a waveform like the one in the picture. (I simulated the circuit on multisim cuz I havent got a photo yet.)

The white trail is when there are no metal objects detected.
The red trail is when there is a metal object.
In other words in the presence of a metal the wave takes slightly longer to get back to 0V.

The picture is grossly inaccurate but I hope I managed to get my point across. :P



Am I on the right track?

Lastly, the range that Ive got was disappointing. It appears that there isnt enough depth, as the coil was only 3-4 cm away from the metal object to get a response like the one in the picture.

[taliesin]

Oh my, does it mean I would have to build the whole chunk?

I have got not much time left for this project so I need to find a shortcut

How about linking the wire from Q1's emitter to the switches?

I'd imagine the Schmitt Triggers are made to close the switches when Q1's emitter goes to 12V (which is when the timers output goes to 0V) after the series inverting outputs.



Thanks again guys!

i think you would be hard pressed to reduce the parts count for the surf pi.if that's your point .

[bklein]

To answer your question, yes you could build just the first section of the circuit with the 555, coil driver, and 5534 preamp. Skip all the 4093/4066, integrator, and audio.
You should be able to then do what you show in your first scope shots - and what many of us have shown in discussions about discriminating metal type in the flyback response.
Look at pc soundcard or arduino approaches several on this forum have written about.
You will likely spend 10 minutes looking at this with your scope and then decide you need more help - either from the remaining circuitry or pc software - to indicate target qualities. If you really want to simplify the circuit you could with the luxury of a digital scope. Eliminate the circuit entirely. Ground one end of the coil, scope across it, set your scope trigger for capture, and momentarily touch the other coil wire to the battery and release. It will give you the flyback pulse and this will be different if a target is under the coil. Make sure your scope can handle the flyback voltage - which can be 1KV depending on where you look, battery, and coil characteristics. Normally what we all look at is what is within the area where the back to back 1n914's aren't conducting.

[nelson]

Sufmaster has a no motion detector.

Hi, does anyone know if surfmaster works good has a no motion detector, using the pinpointer function?
Are the detection ranges the same has motion detecting?
I ask this, cause yesterday playing with a small coil, made by network cable, the surfmaster detected a small 1 1/2 inch wire long, 0,5mm in diameter, at a distance of 2 to 4 centimeters. So now i´m asking if surfmastar can work has a no motion detector

Regards

Nelson

[satdaveuk]

pcb etc

H i Everyone
I really like to make this machine and i see quite a few of you have worked hard on it.
Can someone please email me the pcb and the new circuit with mods please.
My email address is: [email protected]
Many thanks in advance
Dave

[mikebg]

Hi, does anyone know if Surfmaster works good as a no motion detector, using the pinpointer function?
Are the detection ranges the same as motion detecting?
I ask this, cause yesterday playing with a small coil, made by network cable, the Surfmaster detected a small 1 1/2 inch wire long, 0,5mm in diameter, at a distance of 2 to 4 centimeters. So now I´m asking if Surfmaster can work as a no motion detector?

Nelson, you can do the job if increase capacitance of C7 (see circuit diagram in posting #404). Measure when you stop over target, how long signaling remains in audible level. For normal targets, six seconds are enough to imitate nonmotion mode. However at small targets the time is shorted.

[Qiaozhi]

H i Everyone
I really like to make this machine and i see quite a few of you have worked hard on it.
Can someone please email me the pcb and the new circuit with mods please.
My email address is: [email protected]
Many thanks in advance
Dave

Have you looked here? -> http://www.silverdog.co.uk/shop/

[yhl]

Surf PI can be detected in the land where it?
I have created SURF PI.
But the sensitivity too high.
What is the tone that it calls out the metal encountered it? Longer experience calls out of metal and then beep. ?

[Qiaozhi]

Surf PI can be detected in the land where it?
I have created SURF PI.
But the sensitivity too high.
What is the tone that it calls out the metal encountered it? Longer experience calls out of metal and then beep. ?

This is a pulse induction detector. It can be used in land, but only for relic hunting. It detects all metals, and does not discriminate. It is best used on the beach where it is not affected by wet sand.

[maikl]

Surf PI can be detected in the land where it?
I have created SURF PI.
But the sensitivity too high.
What is the tone that it calls out the metal encountered it? Longer experience calls out of metal and then beep. ?

I understand how you are made Surf PI. You're satisfied with the sensitivity. You is not clear what it loses sound: it is a motion detector, you have to keep swinging it left - right. See what a little motion and what is non motion detector.

[yhl]

You're right. The detectors have to keep moving around. 26 cm 1 yuan. But do not know where the underground metal?
Gary, I also established a PI, not sensitivity. One yuan, in 13 cm scream. 20 cm induction.

[WM6]

But do not know where the underground metal?

You mean which metal? You mean that you cannot differentiate between metals in ground? You ask for discriminating PI?

If so, you can try this:

Discriminating PI Pulse Star - G

http://www.geotech1.com/forums/showp...&postcount=219