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

[MDfanatic]

Most probably bad or counterfeit LM7812. Grab a genuine L7812CV and it will work as it should.

[YIVANKA]

[MDfanatic]

YIVANKA nice, what are your ABC numbers?

[sbalio1]

Hi yivanka Can you put this pcb faile or sand [email protected]

[YIVANKA]

I’m looking for it.

[sbalio1]

Good i just hsve image for it .

[durmaz]

Zemin dengesi dengesiz. Zahmet etmeyin.

[Tanu]

Hi
felezjoo is my first md
any one can tell me why felezjoo metal detector coil get hum sound?
is it normal?

[MDfanatic]

Tanu do you hear the hum only when you move the coil above ground or does it make the hum even in the air?
Have you washed your PCB with Isopropyl Alcohol?

[ionut_mtb]

I think he’s talking about hum from the coil not from speaker. Yes is normal, if you change the frequency you will notice hum change in pitch, is the resonance of the coil.

[MDfanatic]

My bad, I didn't read his post carefully.

[Tanu]

Tanu do you hear the hum only when you move the coil above ground or does it make the hum even in the air?
Have you washed your PCB with Isopropyl Alcohol?

Thank u

No i can't find 99% isopropyl in this time.but i cleaned using 70% IPA

[Tanu]

I think he’s talking about hum from the coil not from speaker. Yes is normal, if you change the frequency you will notice hum change in pitch, is the resonance of the coil.

Thanks for your reply

Yes, that's what I meant. For the first time I don't hear that sound.
After many days I heard that sound for the first time

[Tanu]

Another problem with the metal detector
When I touch the battery terminal, circuit or black area it becomes unstable. The lcd shows a negative number and when I remove my hand from the md. md gives the target sound & show in lcd

Below I will put a picture of the ABC numbers

[useus]

After replacing the coil cable with a higher quality one rg58 (I already had rg58 but poor quality, now it also detects gold) a strange thing happens: by rolling the cable on the metal detector stick the signal is unstable, it sounds alone and reaches around +25 / - 25 depending on the situation, instead leaving the cable free, only fixed in the upper part, does not cause balancing problems. The abc values are almost perfect. I have been using the metal detector for about 2 years. Latest firmware with counter.