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

[Qiaozhi]

How do you calculate coil?

Coil Calculator

[cvele]

Bravisimo Qiaozhi!
I use it for years and have no idea that it is yours work. It is simply the best!
regard

[Qiaozhi]

Bravisimo Qiaozhi!
I use it for years and have no idea that it is yours work. It is simply the best!
regard

I have also provided a full description of the equations used and how it works in: Inside the METAL DETECTOR - Second Edition - Published 2015
See Appendix A - Air-Cored Coil Calculator.

[lc516]

I have a test,use Lf356 replaces Lf357

Additional 10%

[marin2]

Hello, cvele and everybody
As if by chance
I press the down button
While a piece of iron was under the coil
The numbers are increased to A = 470 B = 600 C = 845
I think my 357 is good
And my coil is not good
I used the calculator

[marin2]

I use the transistor 2n7000 instead of BS170
Is what it is for this that I have a bad delay and the indicative numbers are always low A 30 B38 C70

[lc516]

Originally Posted by 6666
jladre
would it be possible for you to take a reading with your multimeter for me please, if you cannot thats OK.
I am interested in what dc voltage you have on pin 23 with no target, and coil away from all metal, thanks.

I got 3.83 volts.

Is it key voltage of the pin 23 ?

I get a different voltage on pin 23 (4.3V)

Should I check the circuit?

Expect more Information!

[lc516]

8.5 inches, ordinary copper wire(silver plated stranded wire would surely add performance), 22awg, 360uH, 1.2R, double basket wave coil, damping 383R, sensitivity 20 (without annoying noise) freqyency 200, pulse width 130, delay auto, speed 7, integ w 26, ground 2,..im using different transistors, no 12v voltage regulator, no tantalum cap.. For another video sure i can if i have free time its the same result for sure..

Hi everyone

About damping 383R，What is it，How measure it?

I'm a entry-level enthusiasts,so these messages are very important to me. A related post or guidance.

Thanks!

[samii]

Damping R is parallel to coil, original value is 390R 2W. There are 2 x 390R.Damping connected to ground of IRF and parallel to coil.

[lc516]

Damping R is parallel to coil, original value is 390R 2W. There are 2 x 390R.Damping connected to ground of IRF and parallel to coil.

Yes, you'r perfectly correct.
BTW,Does it need to match with coil?

I tested multiple coil,it's difficult to match.

It's not as easy as the designer said.

[cvele]

thank you very much cvele
How do you calculate coil?
I have decreased to 24 turns
But it's always better 37 37 45
Detection coin of diameter 3 cm to 14 cm

Hi marin2,
My apologize because I didn,t believe you about this numbers, now I get them by myself. Problem and solution are simply!
Your mega328p has arduino bootloader ! Just change H fuse from D1 to D9, erase chip, than go again L fuse- E7, H fuse D1, E fuse FC, and burn hex file.
That is all!
Regard

[marin2]

Now i have a problem i coil error i have to change the mosfets and always the problem
I will erase and redo the program
But with lm318 ca gives great numbers.

[karim1980]

Hi marin2
Your problem is from ici . lm318 -ua741-Does not work with the device They give weak numbers Or large numbers
Look for the original one lf357

[cvele]

Hi marin2
Your problem is from ici . lm318 -ua741-Does not work with the device They give weak numbers Or large numbers
Look for the original one lf357

Yes karim1980, that is wright-only lf357 give proper numbers; but 37, 37, 45, gives ONLY LOADED ARDUINO BOOTLOADER! Yesterday i forgot to erase bootloader and guess what? Those numbers appears.
regard

[jladre]