Help to design a PCB for my PI design!

[Eugene52]

Help to design for my P.I. design !

Hello,

to get rid of of the "noise", you have to "correlate" it. Everything, that is deterministic and predictable, that can be eliminated. This counts also to the phase of the disturbing source. "True uncorrelated" noise can not be. Only the band limitting can help in this case (filtering).

One of the biggest noise sources of the design is the 7660. It is not synchronized to the processing element. The ATmega8's PWM output should synchronize the 7660.

Next is the ATmega8 itself, but as long as the code is deterministic on every cycle, this can be correlated and eliminated therefore. Some caution to code branches must be made. So that the branch and the not taken branch should take same time period.

Other noise sources can be the audio part (on target presence) and 50/60 Hz mains hum. As 1843 low passes the amplified signal before digitizing, he eliminates lots of noises. A typical averaging of the signal which achieves obviously good results even the ADC resolution isn't big enough. The other fact is filtering the power supply of the pre-amps (op-amps).

1843 gave you all a possible way of using the micros internal ADC again. But one sample on every cycle wouldn't be enough and you have to take a moving average of the ADC samples (like boxcar integrators).


You may ask yourself and think of a bit, why I am investing so much effort in synchronisation of all the parts. The answer is simple: "correlating possible noise sources".


Aziz

Hello Aziz , You are 100% correct . The Hammerhead has a 7660 also . It would be a better idea to use something different , or designing a high-Speed switching power supply would be better to get a more clean and stable higher voltage .

I am glad you posted this today !!! The programing is very easy . All P.I. programs are very similar , I just found out that the "Gold-Pic3 P.I." programming is Identical to the "Stuart P.I." Progamming ....Also , I have not seen the internal schematic of the atmel , but it must have a lot of internal filtering and also because of the High-Clock frequency . This will be a Great little P.I. when it gets done..................Regards.........Eugene52

[Aziz]

Hello,

to get rid of of the "noise", you have to "correlate" it. Everything, that is deterministic and predictable, that can be eliminated. This counts also to the phase of the disturbing source. "True uncorrelated" noise can not be. Only the band limitting can help in this case (filtering).

One of the biggest noise sources of the design is the 7660. It is not synchronized to the processing element. The ATmega8's PWM output should synchronize the 7660.

Next is the ATmega8 itself, but as long as the code is deterministic on every cycle, this can be correlated and eliminated therefore. Some caution to code branches must be made. So that the branch and the not taken branch should take same time period.

Other noise sources can be the audio part (on target presence) and 50/60 Hz mains hum. As 1843 low passes the amplified signal before digitizing, he eliminates lots of noises. A typical averaging of the signal which achieves obviously good results even the ADC resolution isn't big enough. The other fact is filtering the power supply of the pre-amps (op-amps).

1843 gave you all a possible way of using the micros internal ADC again. But one sample on every cycle wouldn't be enough and you have to take a moving average of the ADC samples (like boxcar integrators).


You may ask yourself and think of a bit, why I am investing so much effort in synchronisation of all the parts. The answer is simple: "correlating possible noise sources".


Aziz

[Götz von Berlichingen]

Touche. Posting a URL would have been very illuminating. I will do some searching.
But still, does spinning a PCB for the PI-111 equate to writing its source code? Sorry, but I don't think so.


Not necessarily a logical extension. But what you were after is not a fair trade.


Good job, Ivconic

The Stuart II Project is right here, on Geotech : http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=/projects/stuart2/index.dat
Forum for Stuart I and II : http://www.geotech1.com/forums/forumdisplay.php?f=17
The PIC is only used to generate 2 Rectangle Signals, so i think there is Room for a few Extras.

Back on Topic : of course 1843's Firmware must be something special -
but the low-noise PCB that he wants is really hard to do, even more on a single Layer.
All i know is that smart routing of Ground and Power Supply Lines is one of the Keys. We have a mix of sensitive Analog Stuff and a MCU here...
I did a few Experiments with the PICs 10Bit A/D, and i had some trouble to
get the Noise out to make good use of these 10Bits.

[okantex]

Hi ,

Thanks to İvconic an Barry for pcb layouts ,they show their good wills again even argues going on her.

1843 ,
why not to do deep seeking PI like delta , can not you do necessary changes , and to get close samples can you add S&H units ,I mean outer ADC unit for micro.

Regards to All
Okantex

[1843]

There is a difference. They design their own boards or pay someone to do it for them. They don't expect someone else to do that part of the work for them at no charge.

If your code is going to be closed and your ego is so big that you believe you are the only one who could improve it, design your own board. Surely you are the only one who could do it right anyway.

HH,
Rip

Hardware of my PI is so simple and it's almost nothing in compare with its source code.
Believe that if I had enough time, I'd design the PCB by myself.

If anyone are needing to change in firmware, I'm doing it friendly. But do not expect to make a lot of changes so that it becomes a deep seeking PI. The frequencies below 650Hz and the pulsewidths more than 100us will be ignored.

Thanks to Ivconic and Barry for their nice layouts.

Best regards,
1843

[1843]

porkluvr,
Thanks a lot for the schematic.
There are some errors in the schmatic:


Best regards,
1843

[Carl-NC]

Was not my intention to start an argument over the code. 1843 seemed to be making little progress getting any help on this project so I thought he might get people more excited by opening it up. But it is his project and he is free to handle it how he wants.

Let's move on...

- Carl

[barry]

Like Carl I do PCB layout to learn PCB layout better.

[UWLocator]

Not necessarily a logical extension. But what you were after is not a fair trade.

You are making an assumption here. I never said I was after anything, and I don't like it when someone puts words in my mouth. I don't really find this project of interest at this point. There are many ideas for PI detectors based on PIC's and micros hanging around. Until they have been field tested, they are simply ideas that have not been proven yet.

1843 named some commercial projects and pointed out the they do not release source code. I simply pointed out that they also did not ask the community to do some of the work for them for free. I did not suggest that he should give the code in exchange for the board design. That is a decision that is his alone to make, as it would be for anyone that produces creative works.

Before you call someone a thief, maybe you should ask some questions and make sure you are clear about what they said.

Rip

[porkluvr]

Mark Pauls shared his source Code for the Stuart II (Assembly, MPLAB Style).
I plan to rewrite it in Hitec-C and add a LCD.
This will be open Source, too, if i ever get it done.

Touche. Posting a URL would have been very illuminating. I will do some searching.
But still, does spinning a PCB for the PI-111 equate to writing its source code? Sorry, but I don't think so.

So, let me make sure I understand this. Since I graduated from college and do work for pay, I am a thief?
Rip

Not necessarily a logical extension. But what you were after is not a fair trade.


Good job, Ivconic

[ivconic]

Even if share code here, i am total ignorant in programming Atmels, so that code would mean nothing to me anyway. Hex file could mean something, only if i manage to somehow build a programmer and programm that uPc. Of course meaning .hex was accurate, not some nasty joke (which will not suprise me at all). Last but not least; i must have a some good interest in making that device, which i dont have at all. I made over 50 PI's so far and i had it enough for this lifetime. I made those just to sell and earn some money. Personally i dont like to work with PI's at all. My favorites are VLF IB's and nothing else. So...conclusion; i dont give a sheet about this project.... True. Yet at the very start i just wanted to contribute here and help man drawing him a pcb, cose he asked for it so many times. I do have some spare time and why not doing that? I like to play with Sprint Layout and exercise drawing various pcb's. That's how man improving skills.
So...aside previous argues...here is my draw. If it suits demands here - fine, if not - fine again. I probably should not take a part in this topic, and i will not continue in future, for sure. Yet, once i started something usually i must finish. That's me.
Bye!

Best regards to Carl!

[UWLocator]

But I never graduated college so I don't know how real thieves do business.

So, let me make sure I understand this. Since I graduated from college and do work for pay, I am a thief?

Rip

[Götz von Berlichingen]

...
I don't see any other programmers sharing source code for a functioning PI, much less for one that transmits a complex waveform.
...

Mark Pauls shared his source Code for the Stuart II (Assembly, MPLAB Style).
I plan to rewrite it in Hitec-C and add a LCD.
This will be open Source, too, if i ever get it done.

[porkluvr]

There is a difference. They design their own boards or pay someone to do it for them. They don't expect someone else to do that part of the work for them at no charge.

True enough, but drawing up a PCB for this project hardly equates to writing and debugging source code. Arguments that 1843 should share source code with the world based on recipricosity because somebody spins a measly PCB are unreasonable and specious. I think one or two programmed controllers and LCD might be fair exchange for a PCB source. But I never graduated college so I don't know how real thieves do business.

There are limits to reasonable generosity. I don't see any other programmers sharing source code for a functioning PI, much less for one that transmits a complex waveform.

1843 could design his own board and tell the moochers to screw-off.

[UWLocator]

The PCB is for all, not me!
When you buy a kit (eg PD3200 or Goldpic), do they give you source code?

In my opinion, people need source code for PI's like Clone-PI or Miner to play with it, maybe...

Best regards,
1843

There is a difference. They design their own boards or pay someone to do it for them. They don't expect someone else to do that part of the work for them at no charge.

If your code is going to be closed and your ego is so big that you believe you are the only one who could improve it, design your own board. Surely you are the only one who could do it right anyway.

HH,
Rip