current consumption of Cyton SD card

abhinandanaggarwalabhinandanaggarwal Zurich
edited September 2017 in Cyton
What is the amount of current consumed by the cyton board with SD Card. It is writtten in this blog http://eeghacker.blogspot.ch/2015/01/estimating-openbci-battery-life.html that it consumes 40mA without daisy and without SD card. 

I want to know the total current consumed with storing going on in parallel. 

Can we add the currents consumed by the sd card and Cyton individually. For e.g. if sd card consumes 500 mA and cyton consumes 50 mA so can we say that the total current consumed is 550 mA during recording ??

Thanks.

Comments

  • wjcroftwjcroft Mount Shasta, CA
    You can measure this with almost any digital volt ohmmeter by using the milliamp measurement capability. You put the meter in series with your power lead, which Chip explained on that blog post.
  • wjcroftwjcroft Mount Shasta, CA
    I also believe the SD card writing is "buffered", that is, data is streamed into a temporary array, then written to the card only as the buffer fills up. So the bursts of higher current would not be continuous, but only every so many seconds. So unfortunately that is going to be harder to catch on your meter, and you would need to integrate that over time to see the real 'average' current demand.

    It might be possible to use some type of digital storage scope (with a long recording time) and a current sensing resistor. Then examining that recorded trace, do your calculation on average current consumed by the SD card over time.


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