Arduino datalogger with microSD card

A simple-to-use and easy-to-assemble data logger with Arduino micro and a microSD card

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If you are facing the need of reading and storing sensor data (analog and digital signals) and do not want to spend a lot of money on an off-the-shelf data logger, I may have the solution for you.

Based on my own need for a simple and cheap system that can store analog data from various sensors (mainly 0-5v ones), I have developed an Arduino-micro-based datalogger that stores data to an on-board microSD card.

This is how it works:
1- Insert a microSD card on the slot (if you don't, the red LED will lit and nothing else can be done),
2- Connect analog or digital sensors (up to 5V max) to the 4 analog inputs and 1 digital (interrupt) input,
3- Supply 5V to the system, either from the USB @ Arduino Micro or the specific blue connector on the board,
4- Press the green button; the data will be logged into the microSD card on '.csv' format, from time to time (adjustable on the Arduino code),
5- The system will log data for as long as there is power supplied.

Here is an overview of the system; why I made it and how it works:

The full explanation, code and schematics is hosted on my personal blog:


Arduino (.ino) code for the Arduino Micro

ino - 4.34 kB - 04/23/2017 at 22:21



Schematic diagram (in Fritzing)

fzz - 12.50 kB - 04/23/2017 at 22:20


  • 1 × Arduino Micro development board
  • 1 × Card reader (microSD) I used the one from Adafruit
  • 1 × MicroSD card (up to 4Gb) Any speed class
  • 2 × LED 5mm, any color
  • 4 × Screw-tipe through-hole 5,08mm connectors Two pins each

View all 8 components

View all 3 instructions

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