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

[useus]

Try it with some earphones if you don't have a speaker and see if the issue from the buzzer or not. I recently noticed there were two schematics of Felezjoo. They differ in the location of C7. One of them has C7 associated with the audio circuit which I do not think it's the right one.

I run mine with a small 8 ohms speaker, however the audio npn transistor (T3) kept getting really hot to the point where it's not functional anymore and had to be replaced twice. As a last resort, I changed the audio voltage from (+12 v) to (+5v) and now it seems to be okay.

Are you sure that t3 is a correctly mounted bc337? Which schematic and pcb did you use?
Have you tested the ohms of the speaker?
I don't have any problems

[Nightryder]

Are you sure that t3 is a correctly mounted bc337? Which schematic and pcb did you use?
Have you tested the ohms of the speaker?
I don't have any problems

It's all good since it's the fourth Felezjoo I made and it's actually on a breadboard for potential modifications

[useus]

It's all good since it's the fourth Felezjoo I made and it's actually on a breadboard for potential modifications

If it is on breadboard then some connection is wrong

[William]

I have a problem with Gerber file not having a boarder in the file, is there one that contains this information in it? Would like to have pcb made but the Gerber I am using failed because it does not have the boarder file in it.

[Aliavazpour]

Hello, I am using this, it works very well, the price is also affordable, I could not find lf357 in the market.

LM318
Small Signal Bandwidth . . . 15 MHz Typ
Slew Rate . . . 50 * 70 V/µs Min
Bias Current . . . 250 nA Max
Supply Voltage Range . . . ±5 V to ±20 V

It will only work with lf357 metal separation. The iron reject option will not work.

[Aliavazpour]

Hello, I am using this, it works very well, the price is also affordable, I could not find lf357 in the market.

LM318
Small Signal Bandwidth . . . 15 MHz Typ
Slew Rate . . . 50 * 70 V/µs Min
Bias Current . . . 250 nA Max
Supply Voltage Range . . . ±5 V to ±20 V

Regarding the LM318, firstly, I am not sure if it will give a correct answer with a simple change and in the current condition of the device that has separation. But even in terms of range in my initial tests, it was not as good as the LF357. In any case, you can use two 4148 series diodes in the output, pin 6 and before resistor 8, to remove the 1 volt offset voltage of LM318.

[zmaj od nocaja]

hello

Today I finished a felezjoo detector with a very sensitive coil with a diameter of 23 cm
the results are as follows :
a square tile made from a soda 6mm can detects at 7cm in the air
Small gold coin diameter 9.86mm and thickness 0.27mm about 0.20g start detects at 14cm
I use the original software with the counter.
It is very stable and calm on the field.
I tried a lot of operational amplifiers, but the best result is with the original LF357.
It is also solid with AD8055.

[zmaj od nocaja]

https://youtube.com/shorts/_fTH52aNM...emzuX597JrMCzg

https://youtube.com/shorts/iSNIlHdPc...kpB_vYNjSbl

[Altair]

hello

Today I finished a felezjoo detector with a very sensitive probe with a diameter of 23 cm
the results are as follows :
a square tile made from a soda 6mm can detects at 7cm in the air
Small gold coin diameter 9.86mm and thickness 0.27mm about 0.20g start detects at 14cm
I use the original software with the counter.
It is very stable and calm on the field.
I tried a lot of operational amplifiers, but the best result is with the original LF357.
It is also solid with AD8055.

Well done!
Thank you for your report!

[Tanu]

hello

Today I finished a felezjoo detector with a very sensitive coil with a diameter of 23 cm
the results are as follows :
a square tile made from a soda 6mm can detects at 7cm in the air
Small gold coin diameter 9.86mm and thickness 0.27mm about 0.20g start detects at 14cm
I use the original software with the counter.
It is very stable and calm on the field.
I tried a lot of operational amplifiers, but the best result is with the original LF357.
It is also solid with AD8055.

Coil details please?

[zmaj od nocaja]

0.17mh
1.3 ohm
2.012mhz SRF

Spider coil

[Tanu]

Diameter ?
coil type/spider coil?
wire size ?
number of rounds?
Auto delay?

[zmaj od nocaja]

Spider coil 23 cm
42 turns
automatic delay 6
wire type: stranded wire with Teflon insulation AWG 22

Settings: frequency 201 hz
manual delayl 0
pulse width 105
ground 7
speed 10

I was able to search the field even with 19 degrees of sensitivity, although I think it has something to do with the software with the counter.
I plan soon to test the difference on the same device with the inserted software without counters.

[Tanu]

Spider coil 23 cm
42 turns
automatic delay 6
wire type: stranded wire with Teflon insulation AWG 22

Settings: frequency 201 hz
manual delayl 0
pulse width 105
ground 7
speed 10

I was able to search the field even with 19 degrees of sensitivity, although I think it has something to do with the software with the counter.
I plan soon to test the difference on the same device with the inserted software without counters.

Are you getting a false signal in the field?
I also want to try no counter version
Please share experience when trying it

[Nightryder]

Running the detector with high speed & sensitivity settings will cause the audio to go off. Also, testing it indoors or even outdoors but near metal or electrical objects will cause that too.

shielding the coil is always a good idea but with the right material. (read the fastcoil making document and you'll find the right material and how you properly do it)



Things to avoid:

1- Magnet wires for making the coil. Instead, use Teflon wire or even better but expensive Litz wire. ( These two types of wires help you to work with low settings for the device. Not to mention they are necessary for making a fast coil)

2- Aluminum foil for shielding.


Good luck!