sounds cool, are you building your own board for this? .
Yes, we are using the expensive ExpressPCB PCB board service. This is only after thoroughly bench testing the
electronic modules software with the Teensy 3.
What we found out is having two SPI devices eg SPI Adafruit uSD card and SPI RTC DS3234 don't
like to play with each other. It seems the sdFat library hogs the bus and plays havoc with the other chip
selects. <-----<<<< Look Out !!!!
http://forum.pjrc.com/threads/17288...ternate-Pin-Functions?highlight=alternate+spi
We decided to nix the SPI DS3234 and drop back to the Maxim-Ic precision I2C DS3231 +- 2PPM or
the DS3232M+ +-5 PPM to provide a precision data logging timestamp.
The layout will include a 8 pin connector, on the bottom of the T3 "carrier board" to hold the Adafruit uSD
breakout board. Since Adafruit added a 3.3 V regulator and SPI noise reduction circuitry, we decided to keep
their breakout board as a plug-in for our data logger. Also, on the "carrier board" layout, will contain
the SCB70 SMT battery boost converter (LTC3525-5) and the precision SMT I2C RTC. The PCB size will be about
the same size as the Teensy 3, which will just plug into the carrier board.
Finding a command line interface (CLI) to run on the Teensy 3 took us a very long time to locate one.
This allows serial commands to setup the uSD and RTC without IDE programming.
http://www.freaklabs.org/index.php/Tutorials/Software/Tutorial-Using-CmdArduino.html
Any spares we make, one will always be reserved for the author of the Teensy 3 low power library.