Data logging: EEPROM vs SD card

Hi all,

I've dabbled with both SDs and EEPROMs:

  • I used an SD card while messing around with the Ethernet shield, mostly because the shield has one anyway. I used it to store a web page and a favicon.

  • Then this weekend I used an EEPROM while investigating how SPI I2Cworks.

It strikes me that as a data logging method, EEPROM's a bit limiting since it doesn't look too easy to get the data out of the Arduino world into say a spreadsheet on a PC. SD card is of course able to slot straight into laptop and the data is accessible.

I'd appreciate thoughts please....

JimboZA:
EEPROM's a bit limiting since it doesn't look too easy to get the data out of the Arduino world into say a spreadsheet on a PC. SD card is of course able to slot straight into laptop and the data is accessible.

Seems to me you are dead right, and I wonder why you would even consider it. Maybe there are some incentives, but I haven't noticed price being one of them.

http://www.ebay.com.au/itm/DFRobot-EEPROM-Data-Storage-Module-For-Arduino-/131058083270?pt=UK_Computing_Other_Computing_Networking&hash=item1e83aba5c6

I wonder why you would even consider it

Only reason I got any eeproms at all, was to have more than 1 component on the I2C bus while I fiddled around with learning that. (Just noticed I said SPI in previous post)

Nick_Pyner:
Maybe there are some incentives, but I haven't noticed price being one of them.

http://www.ebay.com.au/itm/DFRobot-EEPROM-Data-Storage-Module-For-Arduino-/131058083270?pt=UK_Computing_Other_Computing_Networking&hash=item1e83aba5c6

That module is very pricey at over 10GBP, when you consider that RSComponents has the actual chip on its own for under 1 GBP

SD will give so much more 'bang for your buck' in both convenience of use, capacity & price compared to EEPROM memory. The 4GB card here for £4.90 would cost £92.16 for equivalent capacity in the EEPROM's you listed.

Yep, SD card wins hands down I guess, even if you factor in the slight complication of using it, ie needing a socket whereas the EEPROMs connect to their pins.

So I suppose the EEPROM's purpose in an Arduino project is for storage of say manufacture date, serial number kind of stuff, maybe calibration data. Perhaps usage data...

But whatever is stored there, it's hardly feasible to take the EEPROM back to the shop like with an SD card, so an extraction sketch would typically be required if data needed to be viewed.

JimboZA:

I wonder why you would even consider it

Only reason I got any eeproms at all, was to have more than 1 component on the I2C bus while I fiddled around with learning that.

Ah, so you did it for the intellectual exercise.............

I guess that's a valid reason. I made do with an RTC and a 20x4 display. (I'm always mixing I2C and SPI)

and

So I suppose the EEPROM's purpose in an Arduino project is for storage of say manufacture date, serial number kind of stuff, maybe calibration data.

I believe that is what they are about. Information that might be needed in the event of failure but not meant to be removed from the Arduino, i.e. not data.

JimboZA:
So I suppose the EEPROM's purpose in an Arduino project is for storage of say manufacture date, serial number kind of stuff, maybe calibration data. Perhaps usage data...

Or, EEPROM can be used to store a state that you wish to restore (e.g. in the event that the arduino loses power and is powered back up).

BulldogLowell:
Or, EEPROM can be used to store a state that you wish to restore (e.g. in the event that the arduino loses power and is powered back up).

And hopefully this could be do with the built in EEPROM of the ATMega chip.