Hi Rob,

I formatted my SD micro card in FAT32 format and found a small, blank text file written. Thus, I guess that FAT32 was the correct format. I used an older 2GB SD card for this test. Any limits on the SD card size?

Great! There is some SD card code stubbed in to the firmware, but it’s deactivated because the timing messes with stability at runtime.

The meter can handle SDSC and SDHC cards, so the max size if 32GB. SDXC cards will not work.

Will there be some consideration to having much slower sampling intervals?

Yes. The draft design has the user set a wakeup interval in seconds. When the meter is in standby it would wake up onces every N seconds, take a sample according to the settings left when it was last connected to a smartphone, records the results to the SD card and go back to standby.

I’m also working on a way to export the graph views to CSV format, which I can see being useful.

That experiment sounds really cool.

Thank you!