From: yaniv_vi (yaniv_vi_at_yahoo.com)
Date: 2001-12-20 13:11:09
hey jim
so you worked in emc / emi testin and design ?
why didn't you said so before :)
maybe you can help with cheap ways to pass emi testing for our device
(because again were volunters ) , and with cheap ways to pass the
leakage current tests ?
how much would they cost ?
are there ways to design the machine in such a way that such tests
ewon't be needed at , and just by deign you can say , the machine
is o.k. from this perspectives ?
does this kinds of tests needed to be done just for prototype or for
each device (taking in acount that if they don't stand in these
requirement might hurt a person ) ?
thanks
yaniv
--- In buildcheapeeg_at_yahoogroups.com, "Jim Meissner" <jpmeissner_at_mindspring.com> wrote:
> Dear Sade:
>
> My background is analog. How can I help? I have designed
equipment to measure 10 tera ohm (that is 13 zeros) resistors
accurately. That makes this EEG requirement seem like Childs play.
>
> I am in the process of redrawing the schematics of the Brain Wave
Monitor that I built some years ago. I will post them on my website
for anyone who might be interested.
>
> I have done quite a bit of mil spec EMI and EMC testing and
design. Spent weeks at a time working in screen rooms designing
filters.
>
> I might be able to help with your UV sensor project. I have done
some work with super high sensitivity photo detectors to look at the
human aura.
>
> I worked as a consultant for over 30 years and just recently
retired. I would be happy to pass on what I learned.
>
> Juergen P. (Jim) Meissner
> Check out my Website at www.MeissnerResearch.com
> Read about the benefits of the Brain State Synchronizer sounds for
improving your life and health.
> ----- Original Message -----
> From: sademade
> To: buildcheapeeg_at_yahoogroups.com
> Sent: Thursday, December 20, 2001 1:08 AM
> Subject: [buildcheapeeg] Re: modularEEG input stage prototype ...
Some Ideas :
>
>
> I do not know what an earth happened to my first post, all text
> disappeared, and just a quote was posted ...
>
> Well, I just wanted to say that would like to see those who do not
> contribute to the hw or sw design, to contribute $ donations to
> Joerg for making pcb prototypes at pcbpool.de which is an
excellent
> and lowest priced service on earth, at least, that I know of,
second
> comes Advanced Circuits in US, who have offer for 2 layer boards
> for $33 each, have used the latter, and gotten very good results,
> 5 day service, pcpbool has 15 days, but, they have really good
> prices, and even better they are on 4-layer pricing, one can have
> 4 layer board of nice size for $99 there, which is really killer
prize
> as well. And their small series, from 10 and up, are even better
> deals, which should be used for the list to let more people build
> protos, and get ahead with software/hw design progression, so that
> not just few people would have to carry the weight of 200 lurkers
> and nodoers, but that others could also start contributing, or
> take a hike ... I know this idea of using pcbpool was there
before,
> but it is always a good one, and should be done, not just talked
> about.
>
> I have used BBrown ADS1211 4 diff channel A/D part in some
projects,
> and would think that such part would allow using just single stage
> of the INA114's, and make the analog section much smaller, and
> perhaps boost the noise-performance, provided someone better than
> me routed the guardings/shieldings, though, I would like to learn
> more of how to route high-quality low-noise analog microvoltage
> input stages. I used ADS1211 in interfacing to pressure sensors
> and RTD's that provide very low voltage when driven with precision
> constant current generators, and it just is superior to many other
> A/D parts. I am sure that combining it with something like INA114
> and good routing techniques could somehow boost the analog section
> yet, and not cost much more to speak off.
>
> Then, would consider optical isolation layer right after the
> ADS1211, and operate it trough the optosisolated SPI port
> signals, taking total 2 isolator packages to accomplish, if
> using some nice doubles and quads that are out there these days,
> smt, go to very small space.
>
> After that, would throw in possibly either some small risc
> flash microcontroller with hw multiplier, or, consider
> some of the nicer versions of the TI flash DSP's, combined
> with a USB controller chip from some company FTDI, who provide
> a good way to solve the driver problems, and then approach
> the host PC Program with VB and encapsulated C++ made
> VB controls, GUI with VB quickly, graphics with VB quickly, and
> then, suitable USB access control access the USB driver, to
> get the data in fast, and the math portions could be produced
> with Matlab with the C++ code generator that generates C++
> from Matlab.
>
> This way, one set of people could write GUI with VB, one set
> of people could write the Math code with Matlab and Matcom
> or whatever there are these days, and one set of people could
> learn to encapsulate the Matlab generated C code to the VC++
> made VB controls, and one set of people could spend their time
> and effort accessing the USB or creating the USB control to
> interface with the FTDI chip/driver.
>
> But, that is just how I would approach it, even though, I am
> poor writing any PC code, I am sure that I could participate
> in some of the areas though not being the best choice for
> any particularly, but perhaps able to contribute something
> to some of these, at least the embedded side, schematics
> drawing, board designing ( minus being bad analog in shielding/
> guarding, which other people would have to help me to become
> better with ).
>
> Let me know, if anyone sees any potential in these thoughts.
>
> And, in any case, the lurkers, either please throw in plans
> for the software design / break-up top down / modularisation /
> tools / etc, or donate $ to Joerg for parts and protos, or
> help me to learn analog guarding and shielding, so that I
> could attempt a version of the amps+A/D converter the way
> I saw it above, not necessarily viable, but would like to attempt
> it, as I'd have also other uses for the low-noise microvolt level
> amplifier, such as amplifying UV-photodiodes, etc.
>
> Appreciate, Sade R. M.
>
>
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This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:35 BST