arduino help for monitoring and logging

[EccentricAnomaly]

http://efsl.be/

the above link is an embedded filesystem whick should work well with a sd card
I think the idea is you write the code to deal with the serial port ( spi) and it deals with the sd card  and the filesytem

Had a quick look.   I don't know but I suspect that library's a bit big for an Arduino.

[EccentricAnomaly]

simple question.... can you use these boards, etc to monitor temperture (and other stuff) without a pc on...

Yes, but...

I see you mention about SD cards.

...they have pretty limited memory so some sort of expansion is needed for all but the most trivial logging.

I know you need a PC (linux) to program them,

Windows and Mac OS X are also supported (http://arduino.cc/en/Main/Software).

but can it be easily and cheaply made to record the data for say weekly or daily downloads ot a pc which then displays it in th erequired formats CSV for example?

Yes, if you're a bit flexible on either easily or cheaply.  I suspect a couple of solutions emphasising one or the other will appear in this thread in the next little while.

This afternoon I ordered two of these: http://www.mx2.co.uk/default.asp?part=INTSDREAD

One's to go in my laptop bag as they're more compact than the multi-function card reader which currently lives in there.  The other will be ripped to little pieces to scavenge the SD card connector out to wire up to an Arduino (with a few resistors to drop to 3.3 volts) to have a play.  I've also ordered two of the cheapest SD cards on the basis that there's a non-zero probability I'll blow at least one up and having a spare to use with my camera wouldn't be totally inappropriate.

[EccentricAnomaly]

Going back to the file system question: with the SD cards you can either have some code to create or at least write to a proper file system (e.g., DOS FAT-16) or you can write raw data straight to the card in 512 byte blocks.  The advantage of the second is that it's noticeably less code to run on a tiny Arduino: you might actually have some space left to do something interesting to get hold of the data in the first place.

AIUI, from reading the SD card SPI specs ages ago, you write 512 byte blocks which are buffered in the card until you have a full block.  So one consideration is making sure that the last block gets fully written out, unless you don't care about losing the last little bit of data when you turn the logger off.

Another consideration is reading it in.  It's easy under Linux: when you plug the card in to the reader it's mapped to something like /dev/sdb as the raw (block mode) device and you can just open that and read the bytes out.  (If it's got a recognizable file system on it that'll be mounted as /media/blah or whatever or you can manually mount it to get at the files by name.)  I assume that Mac OS X works in a similar way though probably with a different naming convention as it branched off on a different Unixy train of thought a while back.

Anybody know if there's an equivalent mechanism for Windows?  It's a while since I used it but I don't remember anything of the sort.