felezjoo PI(the best pulse induction metal detector that I made until now)

[Vectroum]

Hello, i am thinging to connect felezjoo pi with my android application via bluetooth in order to proccess and visualize values.
Can you please guide in wich pin of atmega is the output?

Thank you in advance.

[MDfanatic]

Pin 17.

[MDfanatic]

You can measure the voltage on pin 17 of the atmega while you are waving a metallic object in front of the coil but I'm not sure about the readings you'll get.
How are you going to process the values?

[Vectroum]

Hello and thank you for the response.

I measured the output voltage on pin 17 when no metal is near the coil and it is 0V(almost), and when a metal is near the coil the voltage is 2.468v.
The output voltage is not equal the sound, the sound is increasing depend of the distance of the metal from the coil(or the size), but the voltage is not increasing.
Is 0v(no metal) and 2.468v(with metal) so its dificault for me to visualize the value.
Is there any other output? Or i am doing something wrong?

thank you in advance.

[Winston2021]

Felezjoo PI variant with all major components on-board (LCD, joystick board).https://easyeda.com/MDfanatic/deepi-smd-metal-detector

404 error at that link.

[MDfanatic]

Vectroum did you measure the voltage output at the speakers?

[MDfanatic]

404 error at that link.

I had to make the project private for now because there were some minor errors and I will release the final version on this topic.

[Vectroum]

Hello.
In speakers the output voltage when there is metal on coil is 2.5v.

[MDfanatic]

At the speakers do you get 2.5V and 0V only? Have you tried to hold a metal object at a longer distance for a bigger amount of time and measure the voltage?

[sbalio1]

hi friend star can you shar here lay6 or pcb for your felewjoo Snap_2021.01.12_10h17m33s_001.png

[Vectroum]

Hello
No, output voltage change depend on the selected tone.
The voltage change is on corresponding the sound change.

[Vectroum]

Hello, iam facing another issue, the volatge output from speakers when i connect them to multimeter is +-2,5v.
But when i connect them to mcp3424 the output becames a stable 12v and wont increase or decrease when metal aproach to coil.
Why this is happening?

[YIVANKA]

Dear 6666， the problem of coil error is still unsolved .https://simplemetaldetector.com/puls...on-fix/:stars:

[mehmet_dag]

The problem of coil error due to 1megaohm resistor, try to find right 1megaohm value by connecting 1k 3w potentiometer instead of 1m resistor or try to install 820k, 600k, 470k, 330k or 220k resistor. And also check coil ohm as between 1ohm and 2 ohm and inductance as between 350mh or 500 mh. IF still continue problem change your LF357n with Lf357h or lf257h or lf157h as military type. And in your connection is right there should be no coil error. Coil error occurs mostly 357 IC or 1m resistor or coil connection and value error.

[YIVANKA]

Thank you very much for your detailed answer. I will try it in the next few days.