Help to design a PCB for my PI design!

[Unregistered]

"Okan, please tell me what you exactly want, by PM"
Why by PM? Why dont you post here. I was right and i know that. This man only asks and take benefits from this place, gives nothing back. Trust me.
I am unregistered because i can not register. My name iz Zlatan. And i know this man from other forums, he is fraud and liar. He will never give anything useable here. Instead he will ask and ask and ask and take everything he can take from this forum.
Yag you should get out from this forum, not me. This is not the place for frauds,liars and syag!

[1843]

Hi all,
I tested the PI. Because of 7660 DC converter, there's a lot of noise at the output of preamp.

The 2 satge preamp really isn't working good...(because of high consumption) so I changed it to the original...like Barracuda.


Now I'm working on the DC converter to get a smooth current from it.

Best regards,
1843

[Unregistered]

So Quiaozhi's work was for nothing? And Carl was not right?
Others can not check your claims as far as you refuse to post hex file here. You can continue with your monologues here and claim anything you want. Nobody can check those.Also nobody can make parallel work and eventually find better solution and help you here. So, what is the point of you to continue posting here such apstract things?
Either share hex file either leave this place.
Just because of problems you met with dual opamp you dont deserve any help. You never took any serious look on first pcb posted here by ivconic. There are two single opamps resolved in best possible manner to void problems you've been talking about here. Although i am not sure that there are no some other mistakes on that pcb. But idea was excellent.
7660 is source of many problems. Most of problems are existing just because you never considered to synchronize it with the rest of device. Obvious proof of your ignorancy.

[1843]

Hey Unreg,
First of all, if any members of this forum(not you!) want me to leave here, I will...FOREVER.
Then, you are free to use all the Carl's suggestions... and the Qiaozhi's PCB is ready to build... Syncing the 7660 is quite easy. So do what you like.

[1843]

HEX

I found a way for reducing the noise of 7660. I don't know which circuit you want to build... But I have my own including these changes:


The my circuit is working very very stable and sensitive.

And here's the HEX file.
PI-111.hex.txt

Best regards,
1843

[Unregistered]

I really dont want you to leave, it is more funny having you here, showing all the arogancy and huge ignorancy at the same time. So please stay, so sonner you will discredit yourself more.
This hex file first need to be checked; is it the real one or just an joke.

[Qiaozhi]

Basic Rules of the Forum

I really dont want you to leave, it is more funny having you here, showing all the arogancy and huge ignorancy at the same time. So please stay, so sonner you will discredit yourself more.
This hex file first need to be checked; is it the real one or just an joke.

Dear Unregistered,

Please read this ->
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Compared to some of the other Treasure & Metal Detecting forums, you will find my rules to be rather simple. I pay for this web site, 100%. I do not accept advertising money from anyone, therefore I do not answer to anyone. Everyone is invited to be candid. However,

• Be polite. Write messages as if you are standing in front of someone talking to them.
• Criticism should be relevant and constructive. If you disagree with something, state your case, and move on.
• Don't post copyrighted material.

Forum activity can be sporadic, so don't be disappointed if your questions get few or no answers. Just try again. Remember, everyone here is a volunteer.

- Carl
-----------------------------------------------------------------------
The original can be viewed here ->
http://www.geotech1.com/forums/showthread.php?t=10526

[Unregistered]

All right, if you say so. I respect your appereance here, so i will listen your advice from now on. Goal of my provocations was to press this man to post and share full project, nothing else. It is stupid situatiuon to talk apstract here about "some" project, without all the elements we need to perform parallel work and examinations.

[Unregistered]

It is unpolite and out of any cultural behavior what i done in my recent posts. I am sorry because of that. But sometimes we must use certain methods and rude "politics" to achieve some results. If i wasn't nerve and harras this man, God only knows when he will decide to share hex file here. Understand?

[Aziz]

Hi all,

the reason for the bad performance of the two stage amplifier version is as follows:
The first stage is an inverting amplifier with its input resistance of 1k. This is too low for such tiny signals. The non-inverting version with NE5534 has roughly 100k input resistance (=input resistance of op-amp).

Another issue is the DC/DC converter. It will produce more ripple noises, when there is more current draw. As I mentioned, the DC/DC converter must be synchronized to the cycle period to have always same and repetitive ripple noises (correlation to cycle period).

A discrete DC/DC converter should perhaps be considered to have lower ripple noises. But there is no other way: it must be synchronized.

Aziz

[1843]

Hi all,

the reason for the bad performance of the two stage amplifier version is as follows:
The first stage is an inverting amplifier with its input resistance of 1k. This is too low for such tiny signals. The non-inverting version with NE5534 has roughly 100k input resistance (=input resistance of op-amp).

Another issue is the DC/DC converter. It will produce more ripple noises, when there is more current draw. As I mentioned, the DC/DC converter must be synchronized to the cycle period to have always same and repetitive ripple noises (correlation to cycle period).

A discrete DC/DC converter should perhaps be considered to have lower ripple noises. But there is no other way: it must be synchronized.

Aziz

Hi Aziz,

Do you think if the DC converter be synced, It can provide enough current for all the parts?

I tested it when Carl suggested, but the ATmega was restarting all the time.(because of voltage drop).

Also the working frequency of 7660 gets half if it is synced.


Best regards,
1843

[Aziz]

Hi 1843,

Hi Aziz,

Do you think if the DC converter be synced, It can provide enough current for all the parts?

I tested it when Carl suggested, but the ATmega was restarting all the time.(because of voltage drop).

Also the working frequency of 7660 gets half if it is synced.


Best regards,
1843

the 7660 is specified only for low current draws. Synch'ing this would not help in this case. A discrete DC/DC converter is capable to deliver more current. Look to my proposal http://www.geotech1.com/forums/showp...&postcount=454 (post #454) for a discrete solution. It will deliver much more current. The higher the current source, the lower the ripple noises and voltage drops.

A simple high current DC/DC converter could be made with mosfet driver IC's (series TC426, containing two drivers). These chips can be configured for different DC/DC converters or paralleled for more current draw. See the data sheet for more info: http://ece-www.colorado.edu/~ecen451...p2/tc426_8.pdf


I personally wouldn't supply the micro on the DC/DC converter side. But it would require much design changes on your schematics. So another DC/DC converter could help here. The clock for the DC/DC converter must be sourced from the Timer/PWM output of the micro. A very simple synchronisation could be made, when on every cycle start (after the TX-on time), the PWM is reprogrammed again. This will compensate the uneven timings to the cycle period. A clock frequency of 10-50 kHz should be enough.

Aziz

[1843]

One way is to use a P-MOSFET for driving the coil, and a synced 7660 to provide the negative rail.
Like the PD3200. What's your idea?

Regards,
1843

[Aziz]

Hi 1843,

One way is to use a P-MOSFET for driving the coil, and a synced 7660 to provide the negative rail.
Like the PD3200. What's your idea?

Regards,
1843

P-MOSFET's have a much lower avalanche breakdown voltage. We need as high flyback voltages as possible, to "kick the target stronger" and get more target signals.
Aziz

[1843]

But the diode in series with the MOSFET compensate it. Doesn't it?

1843