Andy Flind MFD.

[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]

Originally Posted by abdou2014

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?????????

[abdou2014]

Is that right ?

[Geo]

Originally Posted by 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?????????

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 ??

[abdou2014]

It's a joke

[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..

[Bill512]

long time ago...

[abdou2014]

nice job, when did you build it ?

[Bill512]

Originally Posted by abdou2014

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.