Andy Flind MFD.

[Geo]

Hi.
All these years i received so many mails to post the schematic of Andy Flind.
Today i decided to post it here.
Article is in PDF format and it is from EPE magazine.
I would like Admin to tell me if i can do it or No. Article is from year 1995.

Regards:)

[abdou2014]

We waited for this moment for a long time, thank you Geo :)

[WM6]

Geo, first post, then ask. ;)

Admins post a lot of old magazine projects here:
http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=projects.dat
so one more (22-year old project) could not change nothing.

In contrary, admins can delete post (after most of member downloads of course).

[zakari]

HI GEO
That Is GOOD Idea
We Are Waiting8)8)

Thanks So Much

[Geo]

Geo, first post, then ask. ;)

Admins post a lot of old magazine projects here:
http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=projects.dat
so one more (22-year old project) could not change nothing.

In contrary, admins can delete post (after most of member downloads of course).

Hahaha.... no good idea.
I want the members to read the article and these that would like to construct it with modifications. Maybe i am not sure about results.... but they will construct a lrl the same with a commercial one (and very expensive).
So i need the permission of Admins.
I am waiting for Qiaozhi......

Regards:)

[Geo]

Pray to the Saint George (Qiaozhi)....:lol::lol:

[abdou2014]

Qiaozhi is very generous, he posted the full totem schematic :)

[Qiaozhi]

Hahaha.... no good idea.
I want the members to read the article and these that would like to construct it with modifications. Maybe i am not sure about results.... but they will construct a lrl the same with a commercial one (and very expensive).
So i need the permission of Admins.
I am waiting for Qiaozhi......

Regards:)
Carl says that Winborne Publishing gave him permission years ago for older articles, probably including this one. So please go ahead and post it. :thumb:

[Geo]

Thank you Qiaozhi.
Now the remaining problem is the size of the file.
So i will post the file to your email so you to post it here. Do you have the same email as before some years??

:)

[Qiaozhi]

Thank you Qiaozhi.
Now the remaining problem is the size of the file.
So i will post the file to your email so you to post it here. Do you have the same email as before some years??

:)
Yes, please send it to my Geotech email address.

[Geo]

Thanks Qiaozhi.
I have send it :)

[abdou2014]

Happy birthday Geo :)

[Qiaozhi]

Here is the article from Geo:

[Qiaozhi]

Also, while saving the PDF from Geo, I discovered that I had this article from Andy Flind dated 2001:

[brs]

Thanks Qiaozhi
thanks geo

[abdou2014]

Thank you Geo and Qiaozhi :)

[abdou2014]

What gives this peculiarity in this magnetic detector ???

[Mike(Mont)]

Thanks for the info.

There is a cell phone app titled "Tesla Meter" the icon is a power pole. It has an AC magnetic field detector as well as DC. Don't expect it to be nearly as sensitive, but it's cheap, like a dollar or two. Or do a search for EMF detector. You can even find reviews or which is best.

[Geo]

Happy birthday Geo :)


Thank you:)

[Geo]

What gives this peculiarity in this magnetic detector ???

If you mean the Andy Flind then you must search at forum.
Esteban made some modifications and make it a good lrl (as he was telling).
The good is that you can construct the schematic as is (on original pcb) and later to make the mods and maybe the adds. In place of T1 you can use a tuned coil.
With little mods on it there is a very expensive lrl (don't ask me if it works :lol::lol:)

[Geo]

Also, while saving the PDF from Geo, I discovered that I had this article from Andy Flind dated 2001:

George Thank you.
It is an interesting article and i have 2 sensors in lab drawers...

[abdou2014]

Is the preamp necessary ?

[brs]

Hi Geo
has certainly worked on this machine and its results are satisfactory

[Sneshko]

Hi.
All these years i received so many mails to post the schematic of Andy Flind.
Today i decided to post it here.
Article is in PDF format and it is from EPE magazine.
I would like Admin to tell me if i can do it or No. Article is from year 1995.

Regards:)

Thank you very much dear Geo & Qiaozhi!
...And, Happy birthday Geo!!!
Regards in Serbia!
Sneshko

[Mike(Mont)]

Thanks for the info.

There is a cell phone app titled "Tesla Meter" the icon is a power pole. It has an AC magnetic field detector as well as DC. Don't expect it to be nearly as sensitive, but it's cheap, like a dollar or two. Or do a search for EMF detector. You can even find reviews or which is best.

The app is called Tesla Field Meter by JMS Solutions. Of course not nearly as sensitive.

[Geo]

Is the preamp necessary ?

I believe yes.
Esteban was telling that one friend of him found a big silver "treasure" without the use of preamplifier. The commercial lrl use preamp:)

[Geo]

Hi Geo
has certainly worked on this machine and its results are satisfactory

Hi.
i constructed it long many years ago (maybe 10+) with all mods and adds.
Results at my area was not good. It located only some small objects from short distance.
I keep it yet :lol:
It is a good way for someone to construct a lrl and play with it with little money, compared with the money that has the commercial

[abdou2014]

Thank you Mr Geo :

I want to put only one JFET, is it better ?

what is your advice (BF 245 OR 2N3819) ?

I know you do not like working with 59 Khz, what do you recommend me ( 80Khz or 85Khz ) ?

[Geo]

The basic is to put the preampl inside the coil. Also a potentiometer to control the gain of preamp is neccessary. I don't know who freq is the best for your area. Play with all by changing the tuning capacitor. I prefer 80 ... 100Khz.
I attach a photo from the head of my lrl...

[abdou2014]

Thank you !

[abdou2014]

Between the preamp and The Amplifier IC1, what are the changes for (C1 - R3) ?

[Geo]

Between the preamp and The Amplifier IC1, what are the changes for (C1 - R3) ?

Make C1= 47n and connect a resistor 1M between pin2 and ground (IC1a)

[abdou2014]

I'm designing the circuit board . Thanks for your help

[abdou2014]

For the coil I think a big inductor is more sensitive except that it may react to interferences,

what is the best Coil for this device ?

[Mike(Mont)]

Happy Birthday Geo!

Looks interesting enough to experiment with.

[GOLDEN LILLY]

Hi folks, I build an lrl based on the original schematic of Andy with some modification that is more sensitive and directional. Pre-amp is still used, values of the components like capacitors and resistors are changed, audio stage are also changed, Ic's are also changed which make this lrl very reliable to use.

[abdou2014]

That's what I'm doing, you want to help or scare ??? :frown:

[Geo]

In place of speaker you can use a beep generator.:)

[abdou2014]

we connect the audio output directly in the 555, or we add 100nF + transistor between two

resistor 680K ?

[Geo]

Do you have the schematic of Alonso's PD???

[Geo]

Happy Birthday Geo!



Thanks Mike and Sneshko:)

[abdou2014]

We have to change nothing in the original diagram except C1 - R3, you confirmed ?

[abdou2014]

I think (mineoro special series 2000 and Iconos md) are prototipe Andy flind modified ?

[Geo]

I think (mineoro special series 2000 and Iconos md) are prototipe Andy flind modified ?

No....:nono:
I asked you if you have shematic of PD????

[Geo]

We have to change nothing in the original diagram except C1 - R3, you confirmed ?

you will see on the way...
It is better to make a pcb only for beep generator and another one for coil preampl.
Also it is better to use different power supply for beep generator and for preampl.
Only you will see the problems and what mods to make...

[abdou2014]

I'm sorry, I have clone Alonso-PD schematic ,

[indiana jones]

Hi.
All these years i received so many mails to post the schematic of Andy Flind.
Today i decided to post it here.
Article is in PDF format and it is from EPE magazine.
I would like Admin to tell me if i can do it or No. Article is from year 1995.

Regards:)

Thanks Geo:)

for me, one of the best lrl :)

[Geo]

Hi Chris, how are you.
Try this project, maybe to have good results at your are.
:lol:

[Geo]

I'm sorry, I have clone Alonso-PD schematic ,

So you can use the beep generator from PD. A 100nf at input is ok.
Try to connect it to output of IC4.
IC5 is a tone generator, we don't need it because beep generator uses beeper with internal oscillator.

[abdou2014]

Thank you Geo !

Beep generator from PD !

[abdou2014]

.

[Geo]

It is good to connect a 10nF from pin5(555) to earth

[abdou2014]

I'll do it, thanks, I have questions, is it better to add a radio to this device ?

and how to connect the radio to the beep generator ?

[Geo]

Not for the time. First "play" with it so to see the problems and to find the solutions and later if you like you can add a radio.
You must connect it to beep generator (from volume potentiometer).

[abdou2014]

I put nothing between the radio and the beep generator to amplify ?

[Geo]

I put nothing between the radio and the beep generator to amplify ?

A capacitor 100...470n is neccessary

[abdou2014]

ANDY WITH DIGITAL DISPLAY :)

[Geo]

I attach a preamplifier suitable for this device.
If you will look carefully will see that it is the same amplifier (first 2 stages) of passive receiver from Alonso.
Also the same preamplifier uses the Cryfton OBND1?????????:lol:

[abdou2014]

Is that right ?

[Geo]

I attach a preamplifier suitable for this device.
If you will look carefully will see that it is the same amplifier (first 2 stages) of passive receiver from Alonso.
Also the same preamplifier uses the Cryfton OBND1?????????:lol:

Sorry i forgot to attach

[abdou2014]

There is no pot for gain ???

[Geo]

There is one pot at preampl and one at main circuit.
It is better to put preampl and pot near to coil

[abdou2014]

There is not all that in my schema, I think there is another version ???

[Geo]

It is exactly the same (the first 2 transistors). Not so big difference if capasitors are 22n and not 10n.
Potentiometer must be 5k.

[abdou2014]

Do you have any idea about this transformer, name, reference ?

[Geo]

Where did you find it ??:lol:

[abdou2014]

It's a joke :lol:

[abdou2014]

Can this LRL detect a test field 1 year old ?

[Geo]

Before years i wrote that the MFD by Andy Flind is the base of the schematic of Cryfton.
Before days i attached here the article of the MFD so the members who sent me so many emails to construct it. I saw it as a good opportunity to mod it a little (as to put a preampl) and to construct a lrl as the Crypton with so little money and to see if this lrl works and to save so many money. But i don't see interesting and maybe is better to stop here..
:cool::cool:

[Bill512]

long time ago...

[abdou2014]

nice job, when did you build it ?

[Bill512]

nice job, when did you build it ?
thanks, it was 12 years ago (2006)

[abdou2014]

HI .I finished building ANDY detector , I try it with the PREAM and without the NE555 beep generator. it detect TOTEM transmitter and mobile phone at 1 meter, it does not detect the magnet and the electric watch, I want to know if all is well ???

[Geo]

Haha... now you have a Cryfton OBMD-I.
From what i remember you are not very good.
My device was detecting my watches (a Tissot and a Longines) near to coil.
Also was detecting a China watch from 5..6 cm. I saw a video from a member where his lrl was detecting the watch from 9..10 cm far.

:)

[abdou2014]

The LED display works very well, I have a problem in the audio, the sound of the buzeur is very weak, I do not hear it.

[Geo]

Yes but it must detect the quartz watch....

[abdou2014]

Does this LRL have the ability to detect a test field 1 year old ?

[Geo]

I don't know.
some years ago i tried an cryfton at a ancient place (where some other lrls gives signals) without results.
Also with my mfd i found some very small objects but nothing else....:angry:

[abdou2014]

What are the changes that increases the sensitivity , I can not detect a watch ?

[Geo]

Maybe you have bad calibration or bad preamplifier...

[abdou2014]

I do not think everything is OK, preamp first 2N2222 and the second bc238 HFE 700. I noticed: when I leave the first LED on, and I adjust the buzzer Off, the LRL more sensitive than all LEDs off . I need help Mr Geo!

[Geo]

Can you give details of coil and frequency???
do you have potentiometer at preampl output??

[abdou2014]

8)

[abdou2014]

Coil 2X30 turns + Pot 5K pream .

[Geo]

Coil 2X30 turns + Pot 5K pream .

What do you mean 2x30???

[abdou2014]

Like This .

[ASHIL]

ANDY WITH DIGITAL DISPLAY :)

Hi My friend
Can you put this circuit and digital Display`s in here? But if not Personal

[Geo]

Like This .

Why you use 2 coils????

Who is the coils diameter??

[abdou2014]

The diameter of the coil is 16 cm. with 30 turns I detect the transmitter at 1 meter, 2X30 I detect at 2 meters . frequency 80 Khz .if it's wrong what's to change ???

[Geo]

I don't know more....
Now about calibration you must calibrate it so the first led to be on (light) and just little before the 2nd led turn on.

[abdou2014]

is those winding are necessary, and what is their detail ?

what are the changes to detect a watch, I do not think that will detect anything without

reaching this sensitivity ?

[Geo]

If the gain is ok then you must receive the watch (at least if you touch the watch to the coil).
Do you have oscilloscope and signal generator to test the MFD???

The small coils at Cryfton don't do anything. Constructor use them with gold sample and try to catch the phenomenon. He says that this small coils with gold paper is gold filter. Anyway, averyone can say it as he like.....
For me 30 turns are enough, just tune them at 80Khz.

[Geo]

Here a photo from my Andy Flind's MFD as lrl :cool:

[abdou2014]

is there a difference between the coil location :
the coil below the PCB and in front of 12 cm ?
the coil is it shielded ?

[Geo]

No it is not shielded.
The distance is a small secret: lol :: cool :.
So ..... if the coil is near to pcb and to buzzer, then when the buzzer beeps there is feedback to the coil, and all leds turn on and beeps continuely.
If coil is far then .... NO problem.
This Trick is a present for you ...
:)

[abdou2014]

Thank you Geo :) , to be precise, this inconvenience is caused only by the buzzer, or even the PCB ?

[Geo]

As i remember, from buzzer and coil

[abdou2014]

so I remove the buzzer to keep my design , I think it's the speed that made Andy flind MFD particular ?

[Geo]

It is a good way... but if you will see problems remember to move the coil.

[abdou2014]

there is a remark that I would like to have some explanation :
there is OBMD builder that used all regulator 100mA, the small,
and others who have used the 100mA just in the ANDY LM 358, and the others all a big regulator 1A, is there a diference and what is the right choice ???

[Geo]

No Problem, all are the same because the total consumation is lower than 100ma

[abdou2014]

Thank you Geo !

[Geo]

What preamplifier do you use???

[abdou2014]

Your Email ?

[abdou2014]

I have never used the audio stage, only the VU meter and I detect a magnet at 1 meter and TOTEM transmitter at 5 meters, I do not know if the 4066 + 555 will give more amplification or sensitivity ???

[abdou2014]

I have not yet received the email from Géo ???:angry:

[Geo]

If you wil look at my profil will see it!!!

[abdou2014]

Excuse me Geo, I didn't know :)

[abdou2014]

Is it possible to work in VLF ?

[Geo]

who???

[abdou2014]

I'm talking about ANDY FLIND MFD , if yes , is the 16cm Coil is good for this range or we must work with ferrite ?

[Geo]

Yes it is possible to work at VLF.
I believe that it will works the same with ferrite or with round coil.

[abdou2014]

Thank you , I want to know more about 7.1 Khz that you use with your best LRL ?

[abdou2014]

I believe that the two 15cm Ferrite rods have more sensitivity than all the antenna, I made an experiment with it once and I was impressed :D

[abdou2014]

it's not to say that I'm right, I believe that the 15x2 rods gave great results than other antennas only in the circuit I used, and the Antennas gives equal results with Andy MFD :D

[Geo]

One Ferrari is better than a Lada jeep at good road but at mountains the Lada is better:lol:.
I mean every thing for his job....

[abdou2014]

you are right :) , check your email ?

[abdou2014]

Flat spiral tesla coil gives more sensitivity, 7 meters from the transmitter , I think it needs to be converted to infrared :razz:

[abdou2014]

PIC :

[Geo]

Does it "see"the watch now or you want to post a video from an old member???

[abdou2014]

give me a little time I will make a historical modification :lol:

[abdou2014]

Oops, the batteries have dropped, it's a pity I still have not detected the electric watch, but I have good results :)

[abdou2014]

the watch I used has no coil, it is not normal with this high sensitivity and I have not been able to detect it, I think it must this model ???

[Geo]

If your watch is n't the proper... use a wall clock... they have the same machine.

[abdou2014]

COOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOL :razz:

[abdou2014]

I succeed, a flash every one second, thank you Geo ! :)

[abdou2014]

Hi all, I'm going to do another experiment, and tried to work in FM mode, I want to have the opinion of Geo?

[abdou2014]

Hi, what is the minimum and maximum temperature favorable for working with an LRL?

[sinclairuser]

ANDY WITH DIGITAL DISPLAY :)


hi abdou, why did you cover the picture?.:angry:

[Guard]

Hi.
All these years i received so many mails to post the schematic of Andy Flind.
Today i decided to post it here.
Article is in PDF format and it is from EPE magazine.
I would like Admin to tell me if i can do it or No. Article is from year 1995.

Regards:)

Thanks Geo

I somehow finish the MFD.
Ferrite 6khz, 1nf, no preamp, more gain to ic1b, a 1$ chinese clock from +10cm and from sides from 25cm.
Nice mfd, need mods :cool:
Inside lab, it beeps in any spark, and from 7m. to the Northest walls (metal bars).
Away from 50Hz to mountains, has no compass "thinks" and no bips !
I like the gold-bell-sound

Regards
George

[Dubulumach]

1st mod of MFD :)
https://s31.postimg.org/hxqc481ez/Andy_Flynd_Mod.jpg

Ive forgot to put 470pF in negative feedback in parallel with 1Meg biasing resistor.

Best Regards
Dubulumach

[Dubulumach]

2nd mod. :lol:

https://s31.postimg.org/he7x8zk6z/PLL_VCO.jpg

[Nicolas]

Haha... now you have a Cryfton OBMD-I.
From what i remember you are not very good.
My device was detecting my watches (a Tissot and a Longines) near to coil.
Also was detecting a China watch from 5..6 cm. I saw a video from a member where his lrl was detecting the watch from 9..10 cm far.

:)

Hello Geo you have right8)

[Geo]

Hi.
I found this video at Utube.
MFD detects a watch from 20cm.
Also a very good construction.
Congratulation!!!


https://www.youtube.com/watch?v=t8QYU_1DG4Q&persist_app=1&app=desktop&client=mv-google&gl=GR&hl=el

[rxlock2]

https://www.youtube.com/watch?v=NiGuoENQNVg&app=desktop

TV detection over 10 meters

[Guard]

https://www.youtube.com/watch?v=NiGuoENQNVg&app=desktop

TV detection over 10 meters

Also you say.
"10-meter television detection without exhausting the MFD due to the H / M noise of other home appliances".

First ... nice job !

Second, I think that "10-meter television detection" doesn't mean anything.

You tell us that the coil is resonate , with high "Q", at that specific TV frequency (-+55Khz, or whatever), so at 3,5,100, 1000Khz doesn't receive the fluorescent lamps, or what ever else ... ?
I think that every receiver-mfd act like this, when is resonate to a transmitter.

-------

This video i upload it today, is from my first (1st MFD) outside test (+60cm and is very close to metals) !
The sound is low, sorry (beeper inside, no hole, glued oposite to the coil)
Battery test outside from ++10m.

https://www.youtube.com/watch?v=CjQvV9nhDKU

To the end, the false beeps is the North, i turn it to see (i send it to a friend) the green led.
-------

These days my 6th MFD detects the watch easily from +1 meter and after many tests in 7th MFD ..........

The bigger joke is the distance of detection, for a ... "battery charged" - "working" - under ground - huge ... "clock" :D


.

[rxlock2]

It is very interesting. The coil used can be seen around the machine. What frequency does your own work?

[abdou2014]

8)

[abdou2014]

I'll add an auther detector with andy circuit for more distance :D

[abdou2014]

Hi everyone, I had new results after some modification, I think my Andy flind works as a magnetometer, it detects a neodymium magnet at 4 meters, it detects any ferrous object at 1.5 meters, I want have a display circuit that distinguishes between iron and cavity ?
Thank you !

[abdou2014]

I think our friend G?o has an idea on the subject ??? :)

[reza vir]

Hi everyone, I had new results after some modification, I think my Andy flind works as a magnetometer, it detects a neodymium magnet at 4 meters, it detects any ferrous object at 1.5 meters, I want have a display circuit that distinguishes between iron and cavity ?
Thank you !
hi Congratulation
do you test real burid metal?

[abdou2014]

I do not intend to use it for the detection of buried metals, I have two LRLs which works very well, it is for detect cavities , it's magnetometer .

[shahrayar]

Hi everyone, I had new results after some modification, I think my Andy flind works as a magnetometer, it detects a neodymium magnet at 4 meters, it detects any ferrous object at 1.5 meters, I want have a display circuit that distinguishes between iron and cavity ?
Thank you !
Can you send me the diagram I want to make this device
Is there a topic for this device in the forum?

[abdou2014]

The diagram is in the tread ( andy flind mfd ) I just added a ULF preamp with special 10H coil that I designed

[shahrayar]

I found the topic, you only help in unnecessary and useless conversation

[Geo]

Few days ago a friend sent me a new "release" of Andy's MFD. I tested it and it is more more sensitive than mine MFD. A very good implementation from a non enginear guy!!!:thumb:

[Pahom]

Few days ago a friend sent me a new "release" of Andy's MFD. I tested it and it is more more sensitive than mine MFD. A very good implementation from a non enginear guy!!!:thumb:
Good night Geo! If it does not bother you, tell a little about the controls of the device. Which is responsible for what. Your friend refused indication on lm 3915 what do you think with what it is connected ?.

[Geo]

It is something difference. My friend disconnected the Andy Flind's pcb and connected a pcb from data comunication with high gain.
See the new photo with text at every control.

[Pahom]

It is something difference. My friend disconnected the Andy Flind's pcb and connected a pcb from data comunication with high gain.
See the new photo with text at every control.

Thanks!!! I also think to turn off the LM 3915. I noticed that with this node the response from the spark is a little late and reduces the distance by a quartz watch. Until I understand why this is happening. And at what distance does this device catch the movement of a quartz watch? So far, I have a spark from 1.5 volts to 2 meters and a 7cm clock with confidence.

[Geo]

Connect a switch to power supply of LM3915 and check what its better, with or without it.

[abdou2014]

hi, i want to know from the designers of ANDY flind on the results i got with my new preamp,

spark 1.5 V battery 1.5 Meters, small screwdriver when moving 1 Meter, small magnet 1

Meter, and this with 16 cm coil or with 5 cm ferrite .

what amazed me is that at first, if I connected a coil with large inductance I only detect

ferrous metals and magnet them without sparks, but now I detect all with small inductance

coil .

[GOLDEN LILLY]

Hi abdou. What pre amp did you use? Did you use the pre amp of pdk?

[abdou2014]

Not PDK preamp , it's ma own designe

[abdou2014]

I tried my lrl outside, it gives some false signal from time to time , I don't like that ,

I change the preamp and the coil, I replace the coil with a loop like DCH85 one turn .

It is very interesting, better of the DCH with or without TDA because I made all the versions

I do not intend to add a stimulator because the sensitivity is very high

my DCH 85 version detected a spark lighter from 1 meter, and did not react to the hand near

the antenna , I have 3 meter with this configuration and detect the precious metals at 6 cm :D

[humhum]

High İmpedance Preamplifier , first stage was may be from Dear Maister FrancoItaly ;)

[abdou2014]

No , I modified a very sensitive storm detector as preamp :D

[humhum]

This post general Sch was idea for All friend which need High impedance sensitive preamplifier , not for ..... :D

[abdou2014]

new improvement, reacts to the hand and an aluminum plate 40cm x 40cm from 80cm ,

without stimulator, I believe this lrl is better than Alonzo pd :lol::lol::lol:

[abdou2014]

good evening everyone, I succeeded in making a gradiometer sensor, like the FGM or FLC, I noticed that in the ANDY 1 and 2 magnetometer circuit that there is only a display for a single polarity, I need of a circuit which has a reading of both north and south polarity, so that I can do the difference between ferrous metals and cavity , thanks.

[Geo]

new improvement, reacts to the hand and an aluminum plate 40cm x 40cm from 80cm ,

without stimulator, I believe this lrl is better than Alonzo pd :lol::lol::lol:

So you wait to detect a gold coin from 80cm or 8m.....:lol::lol:

[humhum]

So you wait to detect a gold coin from 80cm or 8m.....:lol::lol:

Yes Master Geo , You are Right that only high Sensibility not is enough for catch
phenomenon signal :nono: , need ........... :razz::razz:

[Geo]

Really i can't understand why many members here show how their detector detects an object from 0.1 ... 1m. This is a job for a normal metal detector not for lrl:nono:.

[humhum]

Really i can't understand why many members here show how their detector detects an object from 0.1 ... 1m. This is a job for a normal metal detector not for lrl:nono:.


They will learn over time, it takes a lot of experimentation to get the full result for
meter or Km .

[Nicolas]

They will learn over time, it takes a lot of experimentation to get the full result for
meter or Km .


:razz::razz::razz::lol::lol::lol::lol::lol::D:D:D: D:D km:shrug::shrug:

[abdou2014]

Really i can't understand why many members here show how their detector detects an object from 0.1 ... 1m. This is a job for a normal metal detector not for lrl:nono:.

it is not the same Mr Geo, these results are without TX, only a receiver, contrary to the metal detector TX RX :razz::razz::razz:

[Geo]

it is not the same Mr Geo, these results are without TX, only a receiver, contrary to the metal detector TX RX :razz::razz::razz:

What it means??? you can make a metal detector without emiting very easy but it will not be a lrl.....

Ohhh and something else..... most lrls don't work good over or near to targets.

[abdou2014]

I built two models which can detect metal without an emitter:

1 - work as a magnetometer, detect only ferrous metals

2- work as LRL, detect non-ferous metals, in junction with am

[humhum]

:razz::razz::razz::lol::lol::lol::lol::lol::D:D:D: D:D km:shrug::shrug:

:razz::razz::razz::lol::lol::lol::lol::lol::D:D:D: D:D km

[abdou2014]

Mr Geo i sent you msg :)

[Geo]

I am interesting to connect a radio inside the Andy's MFD.
TDA7000 is my selection.
Does anyone made this mod???

:)

[abdou2014]

Yes i made it

[abdou2014]

I made all the combinations, and the only problem is the stability, maybe your design is perfect :)

[Geo]

Did you use transformer to drive the beep generator or you connected the audio out directly (via a cap) to generator input???
What radio did you use??

[abdou2014]

i use transformer between TDA radio and beep , I also have another trick of coupling between a commercial radio and the beep , but there is a difference between commercial and TDA :)

[abdou2014]

another sensitive display for TDA :)

[Geo]

Before years when i constructed my first Andy's MFD i had connected a radio via a driver transformer. Now i plan to work a radio based on TDA7000 - LM386 and i am not sure if the output level is enouth to triger the beep generator.
Anyway... the experiment will shows :lol:.

[abdou2014]

direct connection lm386 and beep no, you must modify the beep generator or add a transformer , there is also a trick to know the variation of the input signal of the TDA without using the lm386 :)

[Geo]

I believe that lm386 with gain = 50 is enoutgh. TDA7000 has audio output 75mv.Lets say a normal signal will give output 50mv x 50 gain = 2500mv.
2.5v signal is very very ok to triger the transistor before the 555. Also i can try gain = 200 at LM386.
No reason to connect 8R load to LM386.... a bigger one will be ok.

[abdou2014]

what is the resistance value in series with the capacitor for gain of 50 8)

[Geo]

1K2 in series with 10uF

[abdou2014]

Thank you :) what's the coupling capacitor value did you use between lm386 and trannsistor of beep generator ?

[abdou2014]

I use 100nf , I believe it is better to convert the audio signal .

[abdou2014]

1K2 in series with 10uF

I tried your values and i have 3.9 V at output .

[Geo]

Thank you :) what's the coupling capacitor value did you use between lm386 and trannsistor of beep generator ?

100nF

[Geo]

I tried your values and i have 3.9 V at output .

it's ok...

[abdou2014]

i thnk it's better to connect an auther detector with this coupling 100n :)

[humhum]

Geo , size of my FM Receiver is 50mm X 70mm small PCB (not use TDA7000 ) , in my test
I see that find my garden buried only from Nort and Nort-West way , but this small unit works only when use or mixing with groundet body energy .
About TDA7000 , need fine calibration of correct Frequency and Local OSC , this Freq can't
measure with any unit .

[Geo]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer:lol:. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

[Pahom]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer:lol:. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.
Geo what kind of coil are you talking about, a loop of 14 turns in a place with a 7000 tda or the receiving antenna itself?

[abdou2014]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer:lol:. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

No , the second detector is for electric field :) can you show us a best buzzer circuit to avoid the erratic signals ?

[Geo]

Radio at 100Mhz is for electric field detection??? ... NO
Use a schematic with speaker....

[abdou2014]

Ok 100 Mhz for electric field , so the second must be for magnetic field , but at what frequency ?

[humhum]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer:lol:. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.


Now I will say Yes , Dear Geo , because have other radio type work better for sniffer
(without TDA7000 IC ) .
Also Andreas have in this forum small box (maybe 433Mhz) shniffer for find buried .
Calibration of TDA7000 is very critical fine tuning for buried Frequency .

[abdou2014]

I tried commercial radio and the TDA7000 is better , believe me :)

[Geo]

Radio is not the primary detector so don't spend so much time for it....

[abdou2014]

primary detector is the ANDY circuit, to begin , what is the resonance frequency of a receiver coil ?

[Geo]

There is n't magic frequency!!!!
Tune it near to 80Khz and its fine!

[abdou2014]

Thank you for your help :)

[abdou2014]

ANDY 4016 circuit has low output, almost I can't hear ringing, it is necessary to modify this stage and add something for speaker .

[Geo]

As i remember Andy's output can drive a speaker but you will not have the beep at max signal.Output signal of 4016 increases with the the increase of the input signal as the mdetectors at nomotion mode. This is the reason that we connect a beep generator.
But the problem is that we need a new design....
Until then you can keep the beeper far from the coil

[Pahom]

As i remember Andy's output can drive a speaker but you will not have the beep at max signal.Output signal of 4016 increases with the the increase of the input signal as the mdetectors at nomotion mode. This is the reason that we connect a beep generator.
But the problem is that we need a new design....
Until then you can keep the beeper far from the coilWhat will the new scheme change? If the noise on the circuit comes from the speaker, then the circuit has nothing to do with it. If there is interference inside the circuit, then you need to make a galvanic isolation or power the sound generator from a single power supply.

[abdou2014]

Now it's Ok , very stable circuit with 3 volts supply :D

[Pahom]

Now it's Ok , very stable circuit with 3 volts supply :D

What are you powering from 3 volts?

[abdou2014]

streatcher and oscillator

[Pahom]

streatcher and oscillatorWell, the oscillator is clear to me and what it is for. But what is (the stritcher) did not understand. Maybe not a correct translation.

[abdou2014]

pulse extender or fast pulse receiver

[abdou2014]

the oscillator to drive the speaker

[Pahom]

pulse extender or fast pulse receiver
Thank you, I understood what I was talking about. I have such schemes. And they also work from 3 volts. True, not a lot of non-standard use of microcircuits, but the caffeinth signal-noise is much better than on the LM324

[Geo]

Finally i did n't find solution for the beeper so i moved the beep generator far from main pcb and coil.
Now it works fine!!!, i can adjust it at full sensitivity without any problem.
It don't need any other mod, so now i wait for a good T.H :lol:

[abdou2014]

good work bravo :) can wa have full schematic ?

[Geo]

I have n't a full schematic but i can tell you everything, this project has n't any secret!!!

[abdou2014]

I notice 4 potentiomtres, and I think the 5th is in the front at the preamp , and in the original there are only 3 pots :frown: ???

[Geo]

Here the potentiometer for the preamplifier gain....

[Geo]

The pot with yellow knob is to tune the TDA7000 and the Green to adjust the audio level.
But i don't like it so much and maybe to disconnect it.

[abdou2014]

where is located the TDA antenna ?
and at what point is connected ?
is there an audio amplifier at the output of the TDA ?

[WM6]

i moved the beep generator far from main pcb and coil.
Now it works fine!!!, i can adjust it at full sensitivity without any problem.





Good move, Geo.


Wish you happy hunting.

[Geo]

Thank you Jaka.
Are you OK????

:)

[Geo]

where is located the TDA antenna ?
and at what point is connected ?
is there an audio amplifier at the output of the TDA ?

Ant is located inside the plastic box (half turn) and i think is connected at pin13.
There is an audio amplifier with the LM386.

[abdou2014]

I want to have the coupling details between lm386 and ne555

[Geo]

Nothing special.
A capacitor between 386 and 555 and adjust the potentiometer so when you touch antenna to have a beep.

[abdou2014]

what is the value of the capacitor?
Did you connect this capacitor directly to pin 2 of the ne555 without adding a transistor?
I want a diagram if it's not too much to ask :)

[Geo]

Of course there is a bc547 before 555.
I don't remember the value of capacitor but usually i use 47...100n for this.

[abdou2014]

Ok :)

[abdou2014]

for me, it beeps when my hand is at 5 cm

[Geo]

Decrease a litle the sensitivvity and you are OK.
Good T.H....

[WM6]

Are you OK????

:)


I am hanging in, Geo. Thanks for asking.
Except prolonged winter temperatures here, that make no joy to be outside on TH adventure,
to this day still without fashionable viruses myself, but country go more and more crazy with
all this lock-downs.

I believe in Greece spring is in full bloom, as well as your distant locator development and TH.
Wish you great finds in all fields of life. I am following your interesting LRL post here.

Stay healthy.

[abdou2014]

Decrease a litle the sensitivvity and you are OK.
Good T.H....

Thank you :)

[Zicos]

Happy new year, health to all. I have built the Andy flind 1 and when it comes into operation the first (1) led and the last (10) led light up, the rest of the leds (2/3/4/5/6/7/8/9) are off. and the buzzer works non-stop pot.1 does not change anything nor does pot.2 do anything.what's wrong;;;

[Pahom]

Happy new year, health to all. I have built the Andy flind 1 and when it comes into operation the first (1) led and the last (10) led light up, the rest of the leds (2/3/4/5/6/7/8/9) are off. and the buzzer works non-stop pot.1 does not change anything nor does pot.2 do anything.what's wrong;;;
It shouldn?t be like this, check the soldering, there may be a short circuit somewhere, and wash the board of flux.

[Zicos]

hello my friend PAHOM. i checked it many times and i don't understand what i have done wrong. the problem is in 3915 in its connection or 358 in its output. pot.1 (vr1) what voltage should it have at the end???? does the 3915 connect as it is on the drawing??? or does it have another connection??? I can not understand...

[Geo]

Check the voltage on midle pin of potentiometers, it must be between 0v and +5V. If i remember ok near to 0V it don't beeps.

[Zicos]

the volts on vr1 and vr2 are 0-5volt.vr2 lowers the buzzer. in vr1 the LEDs do not change,,,the first led and the last led light up continuously.

[Geo]

If u deconect the coil then the first led and the last led light up continuously???
Also do u use a preamplifier???

[Zicos]

https://youtube.com/@zicos-jb3fv?si=6G1Y_b1bSqH-4QQ0

[Zicos]

i don't use coil yet because it doesn't work properly.

[Geo]

As i saw the video it works properly except leds. So check all around 3915. If will not find any problem then replace IC. Schematic is corect...

[Zicos]

thank you very much.and Pahom in a private message told me the same.in 3915 i made a vu meter circuit and it doesn't work.

[Geo]

U can attach here the schematic of Andy to see if there is any error.

[Zicos]

I don't have a schematic. i did it on punched board.

[abdou2014]

:)

[abdou2014]

:)

[Zicos]

thank you very much Abdou 2014 for the schematics But I don't have the means to make them. as I have it on the punched board will it work or do I have to make a board????

[abdou2014]

a printed circuit is better, less interference

[Zicos]

hello my friends. i have a copper pot (bagratsi) buried at 0.50 meters depth, almost 9 months if i remember correctly. is there a creation phenomenon,???? and the Andy circuit will show it???? also I made the circle from silver wire 925 (0.9mm) circle diameter 14 cm. I have it buried 0.40 meters along with salt for 2 weeks do you ever think it will have a phenomenon?????

[Zicos]

sorry when will he have fenomeno????

[Geo]

"Phainomenon" needs many years for be creatings:frown:.
Other conditions maybe create some detecting conditiond.
One example is the creating of secondary magnetic field by the buried object if there is a strong underground signal.
But the basic is other.... enjoy your hobby, all the rest comes second :lol:

:)

[Zicos]

good evening.without phenomenon i can't test if something works or not. that's why i asked.

[Geo]

Haha... most members has the same problem...

[Zicos]

it's the pot. this ;;;;