Can pinpointer detecting thin chain?

[Davor]

I tried a few approaches to automatic stabilisation and ... they actually work. Simple RC filtering seem to be a better solution than integration, but in that case I have a bit less control over it's behaviour, the fast and slow thing, and it must be always on. Maybe a nested solution will work the best?
I'll play with it some other time. These simulations take time - which I don't have.

[Nupi]

Hi,

I have replaced R2 with 470K pot
Also replaced R3 with original value 2K2
3x 10nF cap are still in the board
Now, if I turn very slowlly R2, I get to a point where the motor starts moving 1 second, and stops another second, and them moves again (1 sec sotps / 1 sec stops /1 sec stops)
At this point if I move metal over coil, no change at all

I have tried several positions of R2 and R1, but no detection at all

OFFtopic
Nupi, I have no problem to give you my phone, but there will be the language barrier, most of my english is with google translator
I have no problem also to send the pointer to you (if you have the time of course) and pay shipping it back, and your labor

Regards

Hello Nezocas,
It's fine. I will ensure that the pointer does.
I'll give you my address in a PM later.

Regards

[Nezocas]

Hi,

I have replaced R2 with 470K pot
Also replaced R3 with original value 2K2
3x 10nF cap are still in the board
Now, if I turn very slowlly R2, I get to a point where the motor starts moving 1 second, and stops another second, and them moves again (1 sec sotps / 1 sec stops /1 sec stops)
At this point if I move metal over coil, no change at all

I have tried several positions of R2 and R1, but no detection at all

OFFtopic
Nupi, I have no problem to give you my phone, but there will be the language barrier, most of my english is with google translator
I have no problem also to send the pointer to you (if you have the time of course) and pay shipping it back, and your labor

Regards

[Nupi]

Hello , Nezocas.
You can simply run the tests but replace R2, preferably with a variable resistor
of about 470k if you have one, otherwise leave R2 100k and and replace R1 with 100k increase with
each time with 100k to about 400k in total, and in the meantime check.

[Nupi]

I'm not in my electronics mode at this point. Soon.

Hello Davor,
Apology, you're right in order to increase the base resistance.
I had already tried it yesterday noon but to no avail.
This morning I was again working on and saw that I had (to try it out) not raised the base resistance with a variable resistor
from 470k but but decreases with a 47k.
That's what happens when you blindly something grabs a compartment and not checked.
I've now tried with a 470k and work. Sorry

[Davor]

Hello Davor, b.t.w, how do you progress with the Colpitts oscillator and how about the push button stabilisation?

I'm not in my electronics mode at this point. Soon.

[Nupi]

That the motor get 1 second of movement by connecting or disconnecting L2 (lead nº1)
from the powered ON circuit is a good signal.
[He's waking up.(joke)]


Okey step by step now.
Forget detecting with a object and adjusting with R1 that is not necessary now, that will come later.


If all goes well you should get, when adjusting R2, (without metal by the coil) a detection point.
You have to rotate R2 very slowly.
A detection point, which increases in frequency, clockwise and counterclockwise. This is important.


---Connect the coil.
---Place the 3x 10nF Capacitors.
---place R3 a 2,2k
---Remove the motor and place a 1k resistor in place.
---Measuring the DC voltage at the emitter of the transistor.
If the pinpointer not detected should be close to the power supply voltage.
---Now you have to R2 first set at the left or right.That does not matter.
---Now you need to run very slowly to R2.
---THE voltage must come running to a point that the voltage drops to about 5 volts.
This means that the pointer is working and that you can not use that motor here.

It would be easier that you replace the motor with a resistance and a LED to try.


Regards

[Nupi]

Hello nupi,

I have changed R3 to 1K and set the proper voltages with R2 100K pot with L2 (lead nº1 from coil out).... then resolded it
Adjusting sensetivity with R1 still motor
Also no movement from motor, with or without metal over it

Also tried to replace C2 with: only one 10n cap / 2 paralel 10n cap and also 3 10n capacitor ... but no joy

I only get 1 second of movement from motor, connecting or disconnecting L2 (lead nº1) from the powered ON circuit

Tomorrow will try diferent settings

Best regards

I want to solve through the posts because other have ProveIt of
but if that does not succeed, because writing is very dificult for me,
I will call you. Is that an option? Phone number you can give if you want me. Using pp.

[Nezocas]

Hello nupi,

I have changed R3 to 1K and set the proper voltages with R2 100K pot with L2 (lead nº1 from coil out).... then resolded it
Adjusting sensetivity with R1 still motor
Also no movement from motor, with or without metal over it

Also tried to replace C2 with: only one 10n cap / 2 paralel 10n cap and also 3 10n capacitor ... but no joy

I only get 1 second of movement from motor, connecting or disconnecting L2 (lead nº1) from the powered ON circuit

Tomorrow will try diferent settings

Best regards

[Nupi]

Hello Davor, b.t.w, how do you progress with the Colpitts oscillator and how about the push button stabilisation?

"I thought of the automatic tuning for a pinpointer, but then I realised that even the commercial ones
are doing it kinda semi-automatic. Otherwise the clicker trick for improving sensitivity wouldn't work.
When you switch it on it goes into a ~2 seconds cycle of self-tuning, and then it is ready.
Point is that if you let the stabilising circuitry do it's thing all the time,
you in effect get a motion compensated device. If you go with extremely slow motion compensation,
it takes forever till it stabilises. So how about a push button stabilisation.
In a way it would provide some kind of ground balance as well."

[Nupi]

I don't think that the Q factor is too good. 47nF is for C2 is too high.
Adding 100k will not help, I think.
Lowering of R3 to 1k gonna help. If he has further the circuit well built than it must work.
The performance will be less. This is not in theory, but it is tried out in practice.

[Davor]

I'd say your Q factor is too good. No kidding. This oscillator is very touchy on the coil Q and transistor gain, so the trimmer may not compensate if both are too good. You may try 100k in series with a trimmer, or you may go for a lower frequency by increasing the tank capacitance.

[Nupi]

point 1 and 1a/2
1.90 homs

point 1a/2 and 2a
0.65 homs

point 1 and 2a
2.30 homs

coil fully disconneted from circuit

The resistance of the coil are pretty good.
I think, it might be dificult for you to get the proper components.
C2-47nF is too big. But we go try with your components.

Replace resistor R3-2,2k for a 1k resistor and try it out.
Set the voltage values only with R2.
Now have the engine running somewhere when adjusting.

[Nezocas]

point 1 and 1a/2
1.90 homs

point 1a/2 and 2a
0.65 homs

point 1 and 2a
2.30 homs

coil fully disconneted from circuit

[Nupi]

Hi Nupi,

It still doesnt work
I made a few changes to component placement mo make it really small
I made a drawing of my connections but I think they are all good
Also tried your tuning chart. but no sucess

Hello Nezocas.
Can you measure the resistance between:
---point 1 and 1a/2 from the coil.
---point 1a/2 and 2a from the coil.
---point 1 and 2a from the coil.
The coil desconectate
do not worry, we will continue until Nupi pointer comes alive