Black Lives Matter - Action and Equality. ... Adafruit joins the Stop Hate for Profit campaign.
0

Servo Movement Recording (Data Logging?)
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

by Volt Dropper on Thu May 08, 2008 8:48 am

If all you want to know is how to write to an SD card from an Arduino, goodness, google is your friend. Look at the very first hit:

http://jvcideas.blogspot.com/2007/08/ad ... tep-1.html

There are dozens of relevant hits if you dig a bit.

But I think you'll find that's only one piece of a very large puzzle.
Volt Dropper
 
Posts: 30
Joined: Thu Apr 24, 2008 12:58 am

by pd2kplus10 on Thu May 08, 2008 1:44 pm

I looked at the a while ago ... doesn't provide much info. He hasn't been able to figure out how to use it.



Phil
pd2kplus10
 
Posts: 16
Joined: Tue Apr 22, 2008 9:01 am
Location: Hollywood FL

by mtbf0 on Thu May 08, 2008 8:46 pm

so, do you want a file system or to just dump some data on the card?

have you considered a serial eeprom?
User avatar
mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am
Location: oakland ca

by pd2kplus10 on Thu May 08, 2008 11:00 pm

No need for a file system ... just dump it in memory.

I found a 2MB serial eeprom somewhere ... it was cheap like $4 or something. I think it may work. The only thing I would worry about with that is the # of times you can write to it .... it's somewhere around 10,000 writes before it's no good.



thanks,
Phil
pd2kplus10
 
Posts: 16
Joined: Tue Apr 22, 2008 9:01 am
Location: Hollywood FL

by darus67 on Fri May 09, 2008 11:02 am

The flash memory in SD cards has the same problem.

Even so, if you were to erase and re-write the thing 10 times a day,
every day, it's still good for nearly three years. By then it's obsolete.
"He's just this guy. You know?"
darus67
 
Posts: 246
Joined: Wed Sep 26, 2007 10:25 pm
Location: Minnesota, USA

by pd2kplus10 on Fri May 09, 2008 5:25 pm

I thought the memory used in SD was good for much longer.



Phil
pd2kplus10
 
Posts: 16
Joined: Tue Apr 22, 2008 9:01 am
Location: Hollywood FL

by darus67 on Fri May 09, 2008 5:32 pm

I'm not sure how many cycles it's good for, but it still has a finite lifetime.
"He's just this guy. You know?"
darus67
 
Posts: 246
Joined: Wed Sep 26, 2007 10:25 pm
Location: Minnesota, USA

by mtbf0 on Sat May 10, 2008 8:02 am

one thing about sd cards is that they require 3.3v. so you need dual power supplies, (i guess you'll neeed this anyway if you're going to use an mp3 decoder), and voltage dividers on all the inputs to the sd.

eeproms can be had as 5v parts and here's a tutorial i found that describes hooking up a 64k atmel part to the arduino.

http://www.arduino.cc/en/Tutorial/SPIEEPROM
User avatar
mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am
Location: oakland ca

by adafruit on Sat May 10, 2008 1:35 pm

pd2kplus10 wrote:I thought the memory used in SD was good for much longer.


sd cards are quite sneaky, inside theres a microcontroller that keeps track of what blocks of memory are used and re/distributes them 'evenly' so that they all have even wear ("wear leveling")

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

by pd2kplus10 on Sun May 11, 2008 6:20 pm

That 64KB EEPROM link is nice. I think I will start with that for now and see if I can make this work.

Has anyone seen this: http://www.futurlec.com/Mini_FLASH.shtml

... looks pretty cool. 2MB memory and cheap.



thanks,
Phil
pd2kplus10
 
Posts: 16
Joined: Tue Apr 22, 2008 9:01 am
Location: Hollywood FL

by mtbf0 on Sun May 11, 2008 7:48 pm

interestingly, that flash part is also available in an mmc/sd form factor and i think i've got a device that uses it, so if you tire of the serial eeprom and switch to the dataflash let us know.
User avatar
mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am
Location: oakland ca

Please be positive and constructive with your questions and comments.