sd card logger
 

saw this, looks like if you tap the tx, 5v and ground leads on a guino you can log it to a microSD card:
SparkFun Electronics - OpenLog

a 2 gig microSD card should hold about 578 days worth of logging.

It's open source too, so if you would rather build your own, go for it.

I'll get one on order.

Here's another one:

Quick & simple Arduino temperature logger - EcoRenovator

Thanks for the post. This looks like a pretty nice solution to logging that doesn't involve hauling around a laptop.

Yay! Now just need a GPS hooked into there so that GPS and FE data is saved together... <hint, hint>

lol, you might be able to hack it to take two inputs and write two files using softwareserial. the onboard 328 looks pretty lightly loaded.

I added SD to my 'guino, using Arduino Forum - SD card read/write with Arduino as my starting point. Rather than using all those 3300 & 1800-ohm resistors, i used a single IC (74HC125N i think). Someone somewhere said newer SD cards may not work with the resistor method. A 3.3v regulator may also be required, though my arduiino has it built-in via the FTDI chip.

The nutshell: it uses digital pins 10-13, which are currently in use by the LCD, so i had to rewire the LCD in 3-wire mode, which also requires an IC (74HC164 or equiv).

Hardware cost: as low as $1.00 for the 2 chips. I built 2 different card slots, one using a microSD-to-SD adapter; for the other, i salvaged a SD connector from a junked phone or something. My guino was cut, desoldered, and resoldered, though it would have been preferable to build one clean from the start.

Memory requirements are roughly 2.5k eeprom for code, 520 bytes RAM (including the 512b r/w buffer).

Data portability: a little tricky. My 168 didn't have room for the full FAT library, so the guino has to maintain its own filesystem on the SD. Data needs to be extracted by scripts on your PC. Not the end of the world if you're a hacker type, but definitely not grandma-friendly. Card size limit is 2gb. SDHC support would have complicated things a bit, and like dcb said, you get eons of logging on the small cards.


I had started writing up a post detailing the 3pin LCD and SD stuff some time ago, then v0.86 was released, and i didn't know if/how the addon would fit in, so i dropped it. I'll try to post it up if there's any interest, and when i get the time. I also haven't been using the SD, as it's on my spare 'guino, which i haven't figured out how to install in my TDI Jetta A3.

I'm not bent on integrating the sd card, that is fine as an offloaded function. but It might be useful to have the guino start xmiting analog reads from the two unused analog pins. Might even want to free up a couple more analog pins and forget the spare pwm pins. Then the logging folks could hook up map/o2 sensor/throttle pot/??? And it should be possible to do some after-the-fact/realtime computations on those as well, i.e. load/bsfc.

Thanks guys for posting these links. I like the idea of logging, and then analyzing trends in a spreadsheet. :D

nickdigger, did you do this with a preassembled MPGuino? Do you know if it is doable with the preassembled flavor? I ask because I am having difficulty finding a OBD device that will provide me inst mpg for Dodge vehicles...because they do not use a MAF. If I can record straight off the MPGuino to an SD card, that would fix the problem!