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

[ionut_mtb]

The end

thanks for your advice and help!

[ATTACH]49719[/ATTACH]

if one day I feel like it I will try to write the code from scratch, unfortunately the author does not update the project anymore and I am of the idea that it can be improved, perhaps also by inserting the motion option

good job! Calibration button is the same as down button, why did you installed another?

[useus]

good job! Calibration button is the same as down button, why did you installed another?

thanks!
it's more comfortable and you can keep your other hand busy

[ricalbertvig]

you know what is the difference between the 2 versions?

[ricalbertvig]

Does anyone know if the author has released a version other than 3.35?

[ionut_mtb]

Does anyone know if the author has released a version other than 3.35?

There is no new version. I think 3.35 is the final version as per author site.

[Boadil]

WRONG, SORRY

[Boadil]

hi all! this is a Felezjoo clone?
https://newhobby.eu/en/home/28-metal...induction.html

if no, is a good detector kit?

not....

this...

https://newhobby.eu/en/metal-detecto...-detector.html

[chuubaba]

I finally made this detector. Looks very promising. Initially I only used 2.2uf tantalum capacitor and the ABC numbers were 312-743-845. The target i.d worked only within few inches. Discrimination worked at close range. A small gold ring at 4 inches. A large penny size silver coin at 6inches. A car at 1 meter. Ever since I changed with 100uf tantalum the ABC numbers are 463-976-978. With me the only problem is low depth in air tests. I can detect a small piece of wire (maybe <or = 1 gram) at 3 inches. No discrimination. Target ID at very close range. Can't detect coins at distance if swinging them sideways but better depths of approached towards the coil from top. Still depths not impressive despite trying insurances from 100uh to 500uh with 5 inch to 27inch mono coils. With Tantalum capacitors it is least noisy with 11 coil but depths are pathetic. How to improve depth for sideways motion of coil. I suspect coil designed.

[ionut_mtb]

This detector is very simple and it is important to use the exact components that the designer say. I will add some good advice for you and the rest of people trying to build this detector in order to get maximum performance.

-use non-metallic fine wires and connectors to connect the coil and pin headers and flat cable to connect the LCD
-in this circuit, all 100 nanos are laid out to capture noise, and some may not be very necessary, but just be careful! If you want to pay particular attention to the capacitors, take those 3 tantalum capacitors and the 5 pico capacitors seriously
-the delay, if raised, will gradually weaken the gold sensation
-use 1% resistors, the point is how much change in the cold and heat that the more accurate it is, the better its thermal stability.
-noise cancel can be achieved by combining the frequency and frequency of the pulse and the delay and the integral interval, giving a higher gain. In my opinion, the frequency of its 200 interference with the city's 50 Hz noise is noticeable. But with 201 Hz it works much better!
-i strongly recommend flat or spider loops provide about 20% more power than a regular loop, also the discrimination depends a lot! (use the exact wire size for different coil diameter)
Specifications of Different Spider Loop Models Suggested with Lacquer Wire
----------------------------------------- -------------------------
20cm loop: 12.5cm inner diameter - 42cm - about 24m 0.8mm wire.
30cm Loop: 24cm inner diameter - 29cm - about 27m 0.8mm wire.
45cm Loop: Internal diameter 39.5cm - 22cm - Approx 31m 1m wire.
60cm Loop: 55.5cm inner diameter - 18cm - about 35m 1m wire.
Loop 70cm: Internal diameter 65.5cm - 17cm - Approx 38m 1m wire.
80cm Loop: Inner Diameter 75.5cm - 16cm - About 41m Wire 1mm.
90cm Loop: Inner Diameter 85cm - 15cm - About 43m 1.2mm Wire.
Loop 100 cm: Internal diameter 95.5 cm - 14 rounds - about 45 m 1.2 mm wire.

The coil does not need to be exactly 350 uH and 1 ohm! This is a suggested limit for achieving the right range with the correct separation. So a capacity of 300 to 400 uH, even a little more or less and a resistance of 0.5 to 2 ohms still works well. So you don't need to look for exact figures. Big coils should not be tested indoor!!! For me, also 30cm diameter coil is hard to test indoor , keep it away from big metal when testing.

-be sure to use a coaxial cable like the RG58 without foil
-coils does not have shield, this will affect the operation and discrimination
-pulse width setting depends on the loop specifications (in order to get ABC number close)
-the separation number or ID is based on accurate calculation on the waveform and only 3 numbers must be partially correct for proper operation
-wet ground is a problem for all devices, raising the loop higher than the ground and lowering the pulse width and working with low frequency and ultimately reducing the degree of sensitivity are among the key things that help to get an acceptable response in these situations
-the proper lithium battery in this device is specifically 5-cell 21V. Do not use DC-DC converters - have noise
-so be sure to use the piezo loudspeaker so that the noise will not be pushed into the circuit when it is sounded and the balance will not disturb
-resistors 9, 10 and 11 and capacitors 10, 11 and 12 play a greater role.
-let this machine run for a couple of minutes and then balance again for thermal equilibrium
-delay is well over 20. Under 18, the machine becomes very sensitive to fine metals
-in addition, for true exploration of the earth, I recommend the 12-sensitivity
-if ABC numbers are low this means that LF357 used is fake
-mosfet no need heatsink
-keep components close to the board, clean the pcb very good after finish soldering
-no need to use shielded case for detector, only id you have many interference (use only non ferrous shield)



Most of the data i wrote is translated from iranian forum, written only by it's designer Mr. Hamid.
If you take take this advice here the detector should work at best performance. If you want to experiment with other stuff i cannot help you. You can use this settings to get best depth in air tests (aprox 45-50cm for a coin with 30cm diameter coil) but in the field you need to experiment a lot and modify them.

Air test settings: Freq 201, Pulse 150, Delay 0 (for most sensibility to small items), Ground 10, Speed 10, Sens 18 (adjust at maximum you can without having chatter) Integ44, Iron reject must be adjusted different from coil to coil.

Author suggested settings for land use are: Frequency 100 - Pulse Width 180 - Delay 30 - Off Ground - Speed 8 and Sensitivity 12. However, maintaining the correct loop distance from the ground is always the most important factor for good stability, especially on poor terrain.

[ionut_mtb]

https://youtu.be/6r4w736aCWk

air test on gold, 12cm coil spider

[ionut_mtb]

Some coils:

[chuubaba]

If someone can post appropriate files for these coil forms so to get them cut from cnc machine in my area.

Jonny What are the depths if you swing the targets instead of dropping them towards the coil?
I have lots of hope from this m.d. My components are same value as prescribed. I have two boards to try different combinations. One board has no U4 but both are running on 12v battery.
I think EMI is a big big issue in this board; Not cleaning the solder-paste residue gave me coil errors. Maybe a better layout is required. Ferrite beads sounded a excellent idea but no experiments shown on the thread.
I heard there are people using pots instead of few resistors/ damping resistors and getting best results with mono coils but i could not understand their placement and specifications.
Contrary to your observation my change of C6 and C12 from polarised radial to tantals has killed the ABC numbers, the discrimination and the depth.

[ionut_mtb]

If someone can post appropriate files for these coil forms so to get them cut from cnc machine in my area.

Jonny What are the depths if you swing the targets instead of dropping them towards the coil?
I have lots of hope from this m.d. My components are same value as prescribed. I have two boards to try different combinations. One board has no U4 but both are running on 12v battery.
I think EMI is a big big issue in this board; Not cleaning the solder-paste residue gave me coil errors. Maybe a better layout is required. Ferrite beads sounded a excellent idea but no experiments shown on the thread.
I heard there are people using pots instead of few resistors/ damping resistors and getting best results with mono coils but i could not understand their placement and specifications.
Contrary to your observation my change of C6 and C12 from polarised radial to tantals has killed the ABC numbers, the discrimination and the depth.

My 12cm coil base was cut with a laser by a friend from textolite, i did not have the file but it is easy to draw. important to make uneven number of grooves.

The depth if you swing the target is the same, machine have also speed settings.

When i hunt i don't do it near town so there is no EMI. i can run detector inside my apartment, emi everywhere, iron everywhere (but only with small coi) with sensitivity 19!

Coil error it is hard to give from coil construction. 300 to 400 uH, even a little more or less and a resistance of 0.5 to 2 ohms still works well. coil error is because components are bad or wrong.

As for the layout designer explained that he calculated every single detail, component placement, ground plane, traces etc.


I had a lot of questions regarding this detector, i was thinking that are a lot of things to improve and i started read the 2500 pages on iranian forum. I'm not an expert in electronics theory and i will never be, my brain is somehow limited, i don't like physics and mathematics, but i like to build detectors as a hobby. After i had read all the thread regarding felezjoo pi on the iranian forum (quite bad translation with Chrome, but understandable) i realized that Mr Hamid, the developer of this detector is a genius. (my opinion) I found the answers to all my questions. He took care of everything, every detail, for all the questions he had an answer. I don't say that is nothing to improve (maybe ground balance / stability), but for the simplicity and cost of this detector it has huge performance. I did not have the time to test this as much as i want, to understand it and use it to it's full potential, i own Sovereign GT and i'm happy with it, is more than enough where i'm hunting.
My ABC numbers are not so good (i did not had the exact wire diameter for coil), i was interested first to get depth, ABC is more important for iron separation. You can try to use potentiometer and then replace it with fixed resistor.

[nikko10]

Dear radio friends-amateurs, I have программатор of AVR USBASP and the program AVRDUDE is set, I can not find FUSE for programming of ATmega 328, I ask for help.THANK YOU!

[gurdal]

Dear radio friends-amateurs, I have программатор of AVR USBASP and the program AVRDUDE is set, I can not find FUSE for programming of ATmega 328, I ask for help.THANK YOU!