It's also nice having something you can make more of and/or modify/fix.
drhoff:
Thanks for the reply. I was thinking that if the bootloader can write to flash, then so could I. However, after some more reading, it seems like it is not something I want to try to tackle.
It's really not that hard even with IDE 0022 and has been streamlined a bit since. I can give you cookbook for 0022 and it will probably work but you might want the newer syntax.
If the 328P flash isn't enough, for truly mass storage you can get an SD module for less than $5 (much less in 3+ qty but don't forget jumpers) and be able to customize your device by changing the SD card and be able to back up your codes as PC files.
These have gone up recently, it's the place and item I bought 3 for $2.60 ea. Must be Christmas...
http://dx.com/p/sd-card-reading-writing-module-for-arduino-deep-blue-142121
The modules work with 5V or 3.3V, I took a leap and didn't get smoke. I used the standard SPI and SD libraries (though IMO the SdFat library allows more options) and got success right away.
Note that my SD card was pre-formatted FAT, as they usually are, it has to be FAT16 or FAT32
I looked up the maker's name from the back (which has changed) to try and get docs and ended up sending them an email with some suggestions to make their site easier. Somehow Mikey, they like me! They will deal direct through PayPal and have cool modules:
http://www.lctech-inc.com/Hardware/
But I don't see a storefront. My contact wrote that anyone may buy from them and I am still waiting for my 1st shipment, should be a week plus Christmas postal system delay. I paid a little for tracking/registered delivery.
Looks like the same thing on eBay for $2.98 and free shipping. That's with a less than 1 minute check.
http://www.ebay.com/itm/New-SD-Card-Module-Slot-Socket-Reader-for-Arduino-ARM-MCU-/280758300478?pt=LH_DefaultDomain_0&hash=item415e7faf3e
Who knows what the price is next year? Could go either way thanks to politics.
You could build your own for less too.