Can pinpointer detecting thin chain?

[Nupi]

Hi,

One more question
Which transistor was used in TR1

My VRT2009 show´s this:

BC560 front view EBC
2N3906 front view CBE

Regards

Hi,
My best results so far has been with the BC560C.
BC560 front view CBE
2N3906 front view EBC
they are both PNP trans.

[Nezocas]

My best results so far has been with the BC560C.

Thank you so much

[Nezocas]

BC560 front view CBE
2N3906 front view EBC

You are rigth
My VRT show´s bottom view (but barelly visible)

[Nupi]

You are rigth
My VRT show´s bottom view (but barelly visible)

I have that problem sometimes with the data from books.
I am looking now mostly these in Google Images.
And compare several images.
Who is most common is usually the proper.

[Waikiki_Sweep]

A suggestion for a waterproof pinpointer.

That is interesting idea with sliding magnet.
Probably more easy is to use Reed switch to turn power with same magnet. Approx $0.50 or cheaper on eBay.



And for tune with same sliding (or rotating) magnet there is a Hall Effect Sensor A1301 which can provide voltage output proportional to magnetic field strength:
http://www.allegromicro.com/~/media/Files/Datasheets/A1301-2-Datasheet.ashx
Only a problem is that Hall sensor voltage have to be converted somehow to manipulate resistance of R1 with it.

[Nupi]

That is interesting idea with sliding magnet.
Probably more easy is to use Reed switch to turn power with same magnet. Approx $0.50 or cheaper on eBay.

[ATTACH]29179[/ATTACH]

And for tune with same sliding (or rotating) magnet there is a Hall Effect Sensor A1301 which can provide voltage output proportional to magnetic field strength:
http://www.allegromicro.com/~/media/Files/Datasheets/A1301-2-Datasheet.ashx
Only a problem is that Hall sensor voltage have to be converted somehow to manipulate resistance of R1 with it.

Nice idea with the Hall Effect sensor. Maybe it's just too difficult for a simple pinpointer.
Waikiki I know you have several good ideas. Tell us more.

Come on people, this is an open thread, where are the other ideas???

[Davor]

I think with a proper integrator this whole thing should be possible to operate with virtually no tuning. Just turn it on and find some treasure.

[Nupi]

I think with a proper integrator this whole thing should be possible to operate with virtually no tuning. Just turn it on and find some treasure.

Would you describe your idea in the circuit can you?
By the way, you've already had some time to try out the Colpitts in practice?

[Davor]

No.
My shack is out of town, and I'm there far less frequent than I wish. So it may take a while.
The way to make this automatic would require a voltage control of the oscillator working point, and the trimmer preset should be set near the sweet spot so that settling time gets reasonably short. The integrator would correct the working point in a way that the oscillator only barely triggers the beeps with no target. There are a few ways to achieve this. First step would be establishing where to apply voltage so that there is a predictable effect on the oscillator behaviour. Integrators are easy.

[Waikiki_Sweep]

Waikiki I know you have several good ideas. Tell us more.

Come on people, this is an open thread, where are the other ideas???

OK. Just catch another one.

I have an idea for you: BLIND PINPOINTER!!! NO INDICATION AT ALL!!!

But how it works? If you using pinpointer for sure you holding metal detector in other hand and your headphones are on.
If you hold your coil close enough to pinpointer you have to hear some interference from its work.
And when your pinpointer find target that noises changing.

So let your pinopointer to communicate with your metal detector and use metal detector coil as a receiver of pinpointer emitting signals.
It will make staff much more simple and convenient especially to use underwater where you can not hear your pinpointer or look on it.

Sure there some experiments are required and may be some changes or tunings for frequencies but it looks doable.

[Waikiki_Sweep]

Where is my Nobel Prize?

[WM6]

The right question is: can pin-pointer (or detector) detecting hypodermic surgical needle placed at distance of 1-2cm alongside of the sensor (not at the tip):

http://www.geotech1.com/forums/showt...2502#post42502

Such detecting is needed to clean places around schools and kindergartens from such dangerous needles.

[Waikiki_Sweep]

The right question is: can pin-pointer (or detector) detecting hypodermic surgical needle placed at distance of 1-2cm alongside of the sensor (not at the tip):

http://www.geotech1.com/forums/showt...2502#post42502

Such detecting is needed to clean places around schools and kindergartens from such dangerous needles.

Looks like it is very tough task. Even if such pinpointer will detect it somehow area it can cover is too small. You will need thousand hours to check school yard inch by inch.

Governments love ruling and regulating so you can just throw them an idea to add into every plastic head of hypodermic surgical needle a small rare earth magnet.
So you will be able to run with sensitive magnetometer and find it fast anywhere.

[WM6]

Even if such pinpointer will detect it somehow area it can cover is too small.

.

Not necessarily, there are pin-pointer with sensor part longer than 20cm, mounted on detector steam it can cover area comparable to detectors.

Problem is surgical needle detectability.

[Waikiki_Sweep]

Not necessarily, there are pin-pointer with sensor part longer than 20cm, mounted on detector steam it can cover area comparable to detectors.

Problem is surgical needle detectability.

Nupi pinpointer detecting by the top end and has short coil. That concentration of field and sensitivity in small area probably allows it to detect small targets even may be that needles.

Pinpointer from the picture has a long coil and I expect its magnetic field spreads more over long coil and sure it has lower sensitivity as result and lower chance to detect such tough targets like that needles.