From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2001-12-18 02:43:01
Hi Joerg,
Thanks for the advice on parts ...
> You are aware that it is not tested and that it might
> require some patches to get it running?
Yes I am aware that I am prematurely ordering here, but
I'm doing a big order at digikey, so if something needs
to change later, no big deal. I am ordering the parts
for both the ModlarEEG and the Biosemi spec that uses
TL062/LT1012/TLC1078. I'm anxious to playing around with
this stuff, so my plan is to proto the Biosemi design
first just for kicks, then I will try etching the boards
for ModularEEG. If I have to build it more than once,
that's okay, because I need the practice.
> Should it not be AT90S4433?
> AT90S4433-8PC should be enough.
Oops, yeah that was a typo. Prices on the Atmel parts
are fantastic (<$7). I have heard that their FPGA and
CPLD parts are very nicely priced too.
>> 5) There are bunch of different 7.3728 Mhz crystals,
>> packaging is either cylinder, HC49 ...
> IIRR I have used a HC49 Type with flat hight.
Hmmm ... digikey has three HC49 packages listed:
HC49, HC49/UA, and HC49/US. Any clues here? Does
it matter if they are 18pF or 20pF?
> (Hey Frans ! If you read this, could you please
> have a look on the RS232EEG-Prototype board ?)
Ah, I looked at the RS232EEG parts list and it
says the crystal is HC49/S. I wonder if that is
the same as HC49/US?
>> 6) Is an LM340T-5.0 1A 5V TO-220-3 Regulator okay?
> TO-220-3 pins have twice the spacing of the 7805
> regulator. It will not fit.
Hmmm ... that one showed up as a 7805 regulator in
the digikey parts search. The following also showed:
Texas Instruments UA7805CKTER (3-PFM package)
Texas Instruments UA7805CKC (TO-220AB package)
NJR NJM7805FA (TO-220F package)
Are any of these okay? What is the right package?
>> I will be connecting this EEG to an embedded PC
>> running off NiMH batteries and powered by a
>> PT6302A regulator... Do you think it would be
>> safe to power both the PC and EEG from this
>> single regulator?
>
> Yes.
>> If so, can I avoid the TMA0505S
> No.
Okay so I can use the 5V regulator above but I
still need the TMA0505S for isolation. The TMA
regulator has input voltage range of 4.5-5.5 VCD.
The PT6302A has input range of 9-30V and outputs
regulated 5VDC. So can I feed the regulated 5V
from the PT6302A into the TMA0505S? Is the TMA
converter there just for isolation purposes?
One more question: sometimes I run the embedded
PC from a 12V 3A AC/DC adapter. This feeds into
the PT6302A. I also sometimes use a vehicle
cigarette lighter power cord feeding into this
regulator. The 9-30VDC input range allows me to
run off AC/DC or vehicle power or NiMH cells
(12VDC). Are there any safety issues with using
the AC/DC adapter or vehicle power (assuming I
have the 6139Ns and TMA0505S installed)? Is it
safe, or can I only use it on battery power?
Thanks,
Doug
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:35 BST