Andy Flind MFD.

[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]

Originally Posted by 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

What 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

[Pahom]

Originally Posted by abdou2014

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

What are you powering from 3 volts?

[abdou2014]

streatcher and oscillator

[Pahom]

Originally Posted by abdou2014

streatcher and oscillator

Well, 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]

Originally Posted by abdou2014

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

[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]

Originally Posted by Geo

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]

Originally Posted by abdou2014

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