Carl's fluxgate Gradiometer ckt.

[Krzysztof]

Hi Damiafix.
See post # 21 Figure 2 and chart post # 18.
This combination means that the output voltage (0-2,5V) AD557 will PIN14/15! (Voltage Repeater).
It also means that the collector current of Q1 is equal to the voltage at PIN14 / 1.62 Kom.
This loads the current C5.
Of course, the resistance of R6 can not be too big, not too much pent-charging current, is also used to determine the operating point LM393 and Q2.
Tension on the C5 and C6 are important for determining size power saws and range frequency.
To this must be sound in reception was nice, otherwise it quickly tired of hearing and harder to recognize the change in frequency.
Subjective feelings are important!
Sincerely, Chris.

[Krzysztof]

Hi Damiafix.
I found something for you.
Winscope can directly or through an additional snap-checked.
http://www.qsl.net/om3cph/sb/winscope.zip
http://www.qsl.net/om3cph/sb/dcwithsb.htm
http://www.elektroda.pl/rtvforum/dow...74aff6ec1dbdca
http://www.elektroda.pl/rtvforum/dow...74aff6ec1dbdca
Best regards Chris.

[damiafix]

Hi Chris,
please, listen yourself the results, from this link.

All the best, Dam.

[Krzysztof]

Hi Damiafix.
Hooray for good ideas, those MP3 are super.
These results show that the R6 is set around 0.5 - 1.5 Kom, to obtain a sensitivity at low voltage.
Coupled test7 as the voltage below 0.5 V blocks Q1, what shown in MP3 (V = 0.2 V) is a signal to the LCD refresh rate from your digital meter!
It turns out that all components are OK.
Now the next test of cooperation and parts AD557 V / f.
Note that the actual system voltage 0 - 2,5V PIN14/15 occurs.
And there it should be measured.
PIN16 is now about 1V higher voltage (0.7 V + (Ic/R6).
Test8.
Measurement conditions: AD557 set separately as in post # 24; PIN14, 15.16 system connected to the V/f on the original PCB; attached to the analyzer enter PIN1 - PIN8 AD557.
Forcing voltage as Test3j - Test3q.
PIN14/15 voltage measurement only controls - should be as before in Test3.
Setting R6: 0, 0.5, 1.0, 1.5, 2, 0, 2.5, 3.0 Kom.
The results of the hearing. MP3 would be nice.
Best regards Chris.

[damiafix]

Hi Crhis,
again here for share the results:


TEST 3j - AD557 Pin 1: 5 volts Other pin to GND
R6: 0KΩ, 0.5KΩ, 1KΩ, 1.5KΩ, 2KΩ, 2.5KΩ, 3KΩ, 4,5KΩ


TEST 3q - AD557 Pin 8: 5 volts, others pin to GND
R6: 0KΩ, 0.5KΩ, 1KΩ, 1.5KΩ, 2KΩ, 2.5KΩ, 3KΩ, 4,5KΩ

You could to see that, from R6 2,5KΩ to 4,5KΩ, is very hard to hear the sound, the last better audible sound is for R6 1,5KΩ, but from R6 2KΩ to R6 4,5KΩ the volume is much low.

Many thanks again for your help.

Have a good day, Dam.

[damiafix]

Hi Chris,
those are the results of the oscilloscope analysis to the Vco, LM393. The points are refered to the fig.1 Simplified VCO and fig.2 Vco Waveforms of the original Carl's document.
I've measured with the LM393 on the PCB.

See yourself:

LM393 I/O:


The VCO as explained from the Carl's document of the FMX-1:


My results, for R6 0KΩ - AD557 Pin8 5v, Pin1/7 GND:

LM393 PIN3 (Input A/B wired, from LM393 I/O: - "A" from Fig.1 Simplified VCO)


LM393 PIN1 (Output A from LM393 I/O: - "C" from Fig.1 Simplified VCO)


LM393 PIN7 (Output B from LM393 I/O: - "E" from Fig.1 Simplified VCO)


Vref1, Pin 2 (B): 3,51v
Vref2, Pin 6 (D): 2,03v

The waveforms of the LM393's outputs, seem inverted, respect to the Fig.2 Vco Waveforms (from the Carl's document) and the Output B "E" for the Fig.1 Simplified VCO is very different from the waveform "E" shown on the fig.2. Maybe there is a error in the nomination of the waveforms of the fig.2, or maybe I should to do the measures with the LM393 out the PCB!?!?

All the best, Dam.

[Krzysztof]

Hi Damiafix.
Everything OK!
In thee is a little mistake.
The description of the scope PIN1 is to be "E" is output to the amplifier speaker.
In the description of the last scope Pin 7 is to be "C" is control PNP transistor.
Since Pin6 is soft (float voltage, depending on the capacitor charging current - the voltage drop across the resistor internal Pin14/13 AD557) is your charts are great!
And now you still care about listening experience and do well Test8 in its entirety.
I asked them to drive the implementation of extortion, as in Test3j until Test3q how you take the time to do the MP3.
Then you can hear the signal frequency and signal level.
It is perfect for pre-selected, yet the extent of your table rezystancjii R6.
This allows for a nice tone and does not deal with this on the ground.
He will be checked.
In trials with 2 FGM3 will not be wondering what you hear, you will no longer sure!
Best regards Chris.

[Krzysztof]

Hi Damiafix.
Now its time for Test9.
Terms: R6 determine to hear loud signal in a wide range.
Set a FGM3, SCL007, Logic Analyzer, AD557, LM in its place on the PCB.
Stimulate sensor and listen.
Test10.
FGM3 Add a second and see what's going on.
Position of both FGM can be anything but on the table!
Stimulates only one FGM.
You are already close to finals and good luck!
Best regards Chris.

[damiafix]

Hi Damiafix.
Now its time for Test9.
Terms: R6 determine to hear loud signal in a wide range.
Set a FGM3, SCL007, Logic Analyzer, AD557, LM in its place on the PCB.
Stimulate sensor and listen.
Test10.
FGM3 Add a second and see what's going on.
Position of both FGM can be anything but on the table!
Stimulates only one FGM.
You are already close to finals and good luck!
Best regards Chris.

Hi Chris,
many thanks, about the waveforms I understood, I've read wrong the schematic; synopsis for everyone:






LM393 PIN3 (Input A/B wired, from LM393 I/O: - "A" from Fig.1 Simplified VCO)



LM393 PIN1 (Output A from LM393 I/O: - "E" from Fig.1 Simplified VCO)



LM393 PIN7 (Output B from LM393 I/O: - "C" from Fig.1 Simplified VCO)


for the next test (9) I hope to make it, as soon possible! Many thanks again!

Best regards, Dam.

[Krzysztof]

Hi damiafix.
Do not forget whole Test8 from extortion how:
Test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q!
Best regards Chris.

[damiafix]

Hi damiafix.
Do not forget whole Test8 from extortion how:
Test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q!
Best regards Chris.

Hi Crhis,
the whole test8 with all the 64 samples, is available at the follow link:

AD557 test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q


Have a good night, Dam.

P.S. I think that this thread will be a usefull guide for those who want to understand, step to step the FMX-1 or to found problems on the own mag!

[Krzysztof]

Hi Damiafix
Bon Travail
Congratulations, great job.
After thinking I'd do a small change in the project, Carl.
1. Since the first 20dB signal distinction wrong, which means poor sensitivity to small signals.
Proposes to discard the R6 and give an additional 2.2 Kom parallel resistor between pins 14/13.
2. To improve the low frequency transmission Replace C7 ovens at 2,2mikroF.
3. Reduce the production of harmonics add a little bit about 1nF capacitor between R9-R10.
Opportunity to experiment. This gives a small low-pass filter.
4. For the "logic analyzer" experiments leave in its place. You can watch the logarithmic signal level measured!
It eats a lot of power but on the table is a big benefit.
Ready for a tour of the MAG will no longer need this analyzer.
Best regards Chris.

[epitopios]

Hi Epitopios,
many thanks for your reply! Yes, it's so strange....your gradiometer, work correctly?

All the best, D.

Hi guys , Damiafix and Krzystzof
unfortunatelly , i order another one which I have it already because the first one have problem , so better for a second one , I will try these days to make progress with the staff.
I watch your progress and i am impressed !!!
very hot days to stay inside , I hope you understand
Regards , epitopios

[epitopios]

Hi Epitopios.
Whether your picture MAG Carl? ?????
And how goes the MAG EPE?
Where the cables go from the center of images (SLC007-AD557)?
You measure something?
Best regards Chris.

Hi Krzysztof
about MAG EPE: I send it to a friend , he is a good electronic and pc-man !!
I am waiting for some information .
cables: no-where ,.................
no measure there
Regards , epitopios

[epitopios]

Hi Damiafix
Bon Travail
Congratulations, great job.
After thinking I'd do a small change in the project, Carl.
1. Proposes to discard the R6 and give an additional 2.2 Kom parallel resistor between pins 14/13.
2. To improve the low frequency transmission Replace C7 ovens at 2,2mikroF.
3. Reduce the production of harmonics add a little bit about 1nF capacitor between R9-R10. .
4. For the "logic analyzer" experiments leave in its place. You can watch the logarithmic signal level measured!
It eats a lot of power but on the table is a big benefit.
Ready for a tour of the MAG will no longer need this analyzer.
Best regards Chris.

did you see better different from your Gradiometer with these changes ??
you have a 9 volt or 12volt/7Amh baterry ??
Regards , epitopios