Problem with Battery Powered Accelerometer w/Data Logger

Hey all,

I’m a long time programmer, but I just recently started a few Arduino projects. One thing I’m working on is a battery powered accelerometer with a data logger. I’m not sure my component choices are the best as I’m just going proof of concept right now, but I’m currently using:

  • an Arduino Micro
  • an Adafruit breakout board with an ADXL345 accelerometer
  • an Adafruit SD Card with breakout board
  • a 3.7V Lithium Ion batter from Adafruit
  • a U3V12F5 Pololu 5V step up voltage regulator

So I wired everything up, wrote the code, and used the USB from my Mac as the power source (no battery involved yet). Everything worked great. No problems that I’ve found yet.

However, when I try to disconnect the USB cable and instead use the battery/Pololu regulator the Arduino Micro seems to power up just find, but the LED on the SD card flashes once and then goes off (it’s normally on the entire time).

I’ve attached a graphical schematic to show how I have the devices wired. I searched and found a few other topics of people having the same problem, but I never found a thread that had a resolution. Any input you can provide would be greatly appreciated.