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

[jladre]

Can you give details on your coil, size, number of turns. Did you use LF357 or a substitute? Anyways congrats on your success it seems to be working very nice.

Hi eclipse. That is a 56cm coil with 400uH inductance made of 2 turns of 26awg CAT cable.. Im planing to make 68cm coil i have a 1mm copper wire her..i hope this would be better. Im using lf356 but im trying to get lf357 problem is only ebay is the option.

[cvele]

Hi Ivconic, I also notice that smaller coil ( 6" basket ) works better than 10" standard, but not good enough,just better.
This is My first experience with this MD but I am not sure that I can make any progress with small coils. This days I will try
bigger coil and observe its doings. Regard.

[ivconic]

Hi Ivconic, I also notice that smaller coil ( 6" basket ) works better than 10" standard, but not good enough,just better.
This is My first experience with this MD but I am not sure that I can make any progress with small coils. This days I will try
bigger coil and observe its doings. Regard.

What results you are achieving with 6" coil?

[cvele]

At first, I must say that my usual replacement of LF357-NE5534 does not work at all: 6" basket coil= little scissors at 10-12cm, coin = nothing! Now, I replace it with TL081 (the only close one that I can find in My shoe-box) and: "Its a kind of magic!" - with 7" spider coil, 400uH-(regular CHANCE-PI coil) and sens 19: 25mm coin go up to 30cm!! UNBELIEVABLE! But theres "catch 21" - poor or none iron-mask (or iron reject). Probably because of no used lf357, so please, if someone use originally op-amp, does it work propperly? Regard
PS- Thank You Ivconic for advice about Atmels EEPROM.

[jladre]

But theres "catch 21" - poor or none iron-mask (or iron reject). Probably because of no used lf357, so please, if someone use originally op-amp, does it work propperly? [/QUOTE]


No! Don't believe on iron descrimination of this device..it so far to be true..

[jladre]

This device is also poor performance in big coils. Just stick on 60cm coil and below.

[eclipse]

Try LF356 instead of LF357. Most of LF357 currently on the market may be rebranded TL071/TL082/LF356 anyways. If you can't get new old stock better don't buy.

[6666]

Most of LF357 currently on the market may be rebranded TL071/TL082/LF356 anyways.

Where does that information come from ?

[eclipse]

Reading through the forum of the author of this devices it's mentioned by lots of people bad performance by some chips, they call these fakes. If this is to believed true, then must be lower end compatible devices, those mentioned by me. Keyword here is "may be". Search for NOS LF357, i.e prefer buying old stock than new for these chips is better.

[6666]

Reading through the forum of the author of this devices it's mentioned by lots of people bad performance by some chips, they call these fakes. If this is to believed true, then must be lower end compatible devices, those mentioned by me. Keyword here is "may be". Search for NOS LF357, i.e prefer buying old stock than new for these chips is better.

Ok I've just ordered a couple of lf356 to check out

[eclipse]

It will work just fine on every schematic that uses LF357, tested on this device also on Delta Pulse.

[ivconic]

Where does that information come from ?

That can be truth, though we don't have material evidence.
Not only LF357; i believe lot of other ic's are faked too.
For example; TL071, TL061 and some others are having usual price 0.4 to 0.8 euros, while LF357 is priced at 1.5 to 2 euros in all local shops.
It is possible to overprint the label with new one, especially if label is "soft" printed and not "carved" on the surface.
Same case is with transistors, especially with expensive power mosfets. I have several cases to compare mosfets with same label and got dramatically different performances on the very same device.
Most secure way is to buy such material from reputable and reliable vendor.
...
This particular case; i am getting ZERO performances with "LF357" i bought in local shop the other day, while with LM318 (having it for several years in my lager) i am getting some so so performances.
Yet all this is still too far away from what i expected from this project.

[dennisgold]

hello. i build this project but no work. the fuses i write low and high and it s ok but ext fuse no record. is on x04. i put fc but no record. the flash is ok but felezjoo no work. the display lcd no power on. i put the resistor from pin 3 to earth then thje display on in black screen. i don t knopw what hapen. sorry for my english. i m cuban and learning for the future
thanks too much for your help

[jladre]

hello. i build this project but no work. the fuses i write low and high and it s ok but ext fuse no record. is on x04. i put fc but no record. the flash is ok but felezjoo no work. the display lcd no power on. i put the resistor from pin 3 to earth then thje display on in black screen. i don t knopw what hapen. sorry for my english. i m cuban and learning for the future
thanks too much for your help

Used avr extreme burner. It is very easy yo used.. You can also google guide on how to used..it is very easy to burn hex especially if you are using usb isp programmer.. No need for encoding command.

[lc516]

My friends,I need your help!!!

I have created circuits on Breadboard,but it wasn't working


1. When the machine is startup, "coil error"show on screen.
2. After a few seconds,garbage characters running across to the screen.

Where did it all go wrong?

http://pan.baidu.com/share/link?shar...&uk=2405639680

http://pan.baidu.com/share/link?shar...&uk=2405639680

Thanks!