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Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

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Yup.  I found a big file of Zippy quotes once upon a time (as
part of the Emacs "yow" command, I think).  I wrote a shell
script that picks one at random for each posting.  It's
surprising how often they seem related to the thread.  Zippy's
like that: you're not always sure what he's saying but it
somehow seems relevent anyway.

Once upon a time, many years ago, I also had random Zippy
quotes attached automatically to e-mails (even internal
work-related ones).  Once e-mail got to be more mainstream, I
decided that wasn't a good idea.  I particularly remember one
recipient's reaction to a Zippy quote about the pope and a
bubble-bath...

--
Grant Edwards                   grante             Yow!  I'm thinking about
                                  at               DIGITAL READ-OUT systems
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Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

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Fun idea! My vote goes to Zippy for moderator;)


Bob


Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
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... snip ...
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You might do well to emulate the CP/M system, as used for script
(submit) files.  The storage was originally based on the 128 byte
sector size of an 8 inch SSSD floppy (and subsequent other formats
were mapped into this).  The submit file consisted of one line per
sector, <cr> terminated.  Although the file was a part of the file
system, the only addressing necessity was sequential sectors.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on
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Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

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___
I'd use a PIC with AD converters and USART, say a 16F877A.  Use the
24FC512 EEPROM for local storage-it holds 64 kbytes or 32 kbytes of
10-bit AD conversions.  You can daisy-chain up to 8 of them for 256K
readings.  When you are ready to process the data, hook up an RS232
connection between the PIC and your computer and transfer the raw AD
readings to the computer.  Then let the computer do all the number
crunching to convert the AD readings to voltages, and create a
voltage.txt file on your computer that you can import into a
spreadsheet.

Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"
My thanks to the group for providing useful input in response to a
poorly defined question.

I had broken my problem statement into three parts.
1. what I wanted to accomplish
2. a view of possible solution
3. thoughts on what hardware might satisfy needs/desires/aesthetics

Unfortunately my original post pureed all into amorphous glob.
My apologies.

I'll break things down in above groupings.

1. What am I looking for
It might be described as "data logger" or a "very large FIFO".

The input will be an RS232 data stream terminated by <CR><LF> of no more
than 100 bytes at 4800 BAUD occurring once per second.

It shall buffer/store at least 10 mega bytes

The output shall be via USB
  1. I wish to take advantage of USB speed
  2. My computer has available USB port(s)
  3. My computer does *not* have available serial port(s)


2. Possible solutions
Flash devices are large and do not require power to maintain data.
There are environments such as FORTH which can presume any mass storage
device/system to be a sequence of nnn byte blocks/sectors/whatever

3. available hardware
Let's just forget how badly I mangled this one ;{


Is this a better problem definition?

Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"

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USB to serial port adapters exist, they are not expensive.

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Flash to store the data in whether flash chips, CF card or other type
is perfectly OK, as long as the logger can address the device either
directly or by keeping track of which sector it is on.

Your own internal flash chips sodler on the board reduces reliability problems
of connectors or wrong type of CF card installed.

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Alternative 1
=============

As myself and others said before look at FTDI USB<->serial adapters, then
have the flash inside the device log the data via RS232 at 4800baud.

Then when you need to talk to the PC use the USB to RS232 adapter at very
much higher baud rate (115000 or higher should be possible on most micros)
Use a simple application on the PC to read the device using a USB pseudo
serial port.

This has the advantage of you DON'T have to add USB hardware and software
as well as the RS232, and you only need ONE serial port. The flash can be
soldered on board a smaller and more portable and SEALABLE weatherproof
device.

Also you don't have to get your USB checked on hundreds of USB combinations
and buy IDs etc..

Alternative 2
=============

Using a CF card in a PC without a file system and doing raw read/writes
has a basic problem. Windows allows raw read/writes when a physical drive
exists and has a drive letter. CF card does not have a drive letter until
the Plug and Play from detecting the CF enumerates it and does an auto mount
including mount a filesystem. Until you either bypass that mounting of file
system or only allow format of device options that windows has on automounting
of a device, you wont be able to do raw read/write on a drive that may not
yet exist to the system. Floppies and other devices can do raw read/write
because the drive physically exists and exists as far as system is concerned.

As someone else has said know what the format of the device is and skip the
filesystem blocks is one way, but bear in mind as the CF cards get larger
they maybe formatted as FAT16 or FAT32 depending on size of the CF card.
That in turn will affect your coding.

CF cards and connectors means all sorts of other reliability issues of the
connectors, CF card brands supported, mechanical considerations for sealing
and durability.



Those are the basic choices, decide what you want from the product as a
whole in usability, reliability and other aspects, using the same serial port
in playback mode means less openings and connections to deal with.

--
Paul Carpenter          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
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Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"
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<snip>

Easy solution - Buy RS232 to USB converter, log data in HyperTerminal on
laptop :)

I've just finished making something similar to what you describe. It has 2
RS232 ports and a CompactFlash card. The RS232 data is timestamped and
stored on the card in the FAT16 file system. Therefore it can be read with a
USB CompactFlash card reader in Windows.

Do you want to buy this kind of thing or make it yourself? What is the
purpose of collecting the data?

Ross



Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"
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You forgot two very important details:
1. Do you only need one of these or do you need hundreds or thousands of
these?
2. Do you want to build one or do you want to buy one?

If you only need one of these and it's OK to buy instead of build, then buy a
used iPaq (or other PDA) from eBay. It's small, cheap, has a serial port, it
has a USB port and it can store 32 or 64 or 128 MB or even more if you add a
memory card. Software to do GPS and/or raw serial data logging is freely
available. I use my iPaq for this purpose all the time.

A few other details which other people have already asked but I'll repeat them
here again:
3. Is there a physical size limitation for this device?
4. Are there any requirements on the user interface?
5. Are there any power consumption / battery life requirements?

--Tom.

Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"
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Only one.



Buy.


I didn't know of PDA's using USB to connect with a desktop PC. I had
only noticed units using RS232 or Bluetooth ( I wish to use neither of
those. )


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Size isn't tightly restricted. It needs to conveniently travel on dash
with accompanying GPS mouse receiver. But availability of PDA with USB
opens up possibility of using GPS receiver that plugs into CF slot. This
is for a home project that I may not use for long so I would like to
stay under a couple of hundred dollars. If the ideas I'm playing with
work,I might use it for a couple of years.

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Not really. I'm willing to trade inconvenience for low cost.

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It needs to be battery operated but will spend most of its operating
time plugged into a cigarette lighter or a wall wart.


Some have suggested a laptop as the logger. Too big. Too expensive.


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Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"

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If either of those options exist then the converters from RS232 or
Bluetooth into USB are readily available and quite cheap (Bluetooth/USB)
dongle is about 10/$14). Although I am also certain that one of the PDA's
allows hook-up to a PC via USB and also features RS232.

--
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Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"
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USB connectivity seems to be standard on e.g. the iPAQ range.

And there's always Bluetooth, of course.

Steve
http://www.fivetrees.com



Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"

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The major problem with Bluetooth/wireless anywhere in system to be
air/spectrum pollution and a pending system security headache. OK I'm
known to be fanatic on certain issues. I am one of those that surfing
*WITHOUT* Java/JavaScript and/or cookies is only sane way to go :)

BTW your previous references to Triangle Digital Services and reviewing
there offerings of development systems encourage me to keep searching
for someone who had already done all the hard work.

dmm from "down under" has recommenced
"About half-way down the page there's a rs232 to MMC/SD card kit using a
pic. http://www.compsys1.com/workbench/ "

That whole site has the flavor of what I was looking for.
I suspect my final solution will be formed around their modules.

Once again my thanks to comp.arch.embedded for their tolerance and
encouragement.





Re: Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?"

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I can understand that attitude.
 
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I thought that the majority of the work had been done by Triangle. This
link describes what you need to order from them and goes on to describe the
software and logging operations (it is almost a one stop shop in that
respect - leaving you just the case, the power supply arrangements and the
assembly of the programme components from the library with any special code
you needed).

http://www.triangledigital.com/man2020f/ch7gps.htm#gpsloggermoduleoperation

I can understand that the cost of that set-up may be more than you desire
to pay for such a capability and I won't hold that against you (or anyone
else). For some jobs I know the basic boards can be too expensive to
consider. I can also understand that the Triangle modules may be physically
too large for your project.
 
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Looks like a very small and neat module (I am assuming you meant about 1/3
down the page and are referring to the Ulrta Compact SD/MMC board). If you
already have a GPS receiver that gives you the position data then this
module could act as your logger and data-go between in any one of the forms
that have been discussed in this thread.

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You are welcome.

--
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