Andy Flind MFD.

[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 ???

[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