Data Logger Shield, a question.
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Data Logger Shield, a question.

by hedon on Sat Feb 16, 2013 3:03 pm

Hello, I have a Data logger shield, the old one, which came unassembled.

I'm about to use it in a project for first time, but I have a doubt. Reading the tutorial I realize that you simply unplug the arduino to shut it down, so I want to know if the shield comes with some kind of protection or shut down delay in the case that the energy is cut off while the shield it's writing to the SD card. As far as I know, this situation it's a possible cause the corruption of the file in the SD.

I'm only curious if the shield has some kind of protection about this, but maybe it would be wiser to write a stop function.
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Re: Data Logger Shield, a question.

by adafruit_support_bill on Sat Feb 16, 2013 3:58 pm

There is no built in protection against that condition.
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Re: Data Logger Shield, a question.

by davidwhiteman on Wed Feb 20, 2013 11:15 pm

This is something that I have been concerned about, too. Can you give me any advice on how/when to unplug the Arduino? Do you use the rest switch? Unplug it from the computer in between data writes when the led on the datalogger is off? If running off batteries, would you, again, unplug the battery in between writes as indicated by the LEDs?
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Re: Data Logger Shield, a question.

by adafruit_support_bill on Thu Feb 21, 2013 10:14 am

In practice i have never experienced corruption of the SD card. But maybe I'm just lucky. Powering down between writes is one sure way to prevent it -as long as you get the timing right. There was a thread a while ago about using the BOD (brown out detect) function of the Atmega chip to detect an impending outage and suppress the writes. If you search for BOD and related logging terms you should be able to find it.
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Re: Data Logger Shield, a question.

by bethesdakid on Wed Feb 27, 2013 10:33 pm

hi Dave... nasa person I presume... go to Jeremy Blum and see his section of the program that checks to see if the logger is in the mode to write... you could run that as a check...
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Re: Data Logger Shield, a question.

by bethesdakid on Wed Jul 17, 2013 11:30 am

Is the logger rail 5V? can it be lowered to 3.3V?
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Re: Data Logger Shield, a question.

by adafruit_support_bill on Wed Jul 17, 2013 11:42 am

There is an on-board 3.3v regulator and voltage shift for the SD card. That could be bypassed to run direct from 3.3v. The RTC, however, runs on 5v.
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