So guys, welcome to the Teensy data logging project!

What I have done in the first hour (literally) of project is set up a basic sketch to read data from an analog input (A5, pin 19 of Teensy LC) and store it to a micro SD card (on a Catalex breakout board) and send the same data over Serial to the Arduino console (on my PC). No worries and no problems at all, so far.

You guys can check the (rather basic) code on my Github page, linked in the proper section of this hackaday entry.