Trouble Powering SD Card with Arduino

Development Boards Arduino
1

I’m hoping someone can help me out. I’m building a GPS logger and I’m having trouble getting power to the SD card. If I wire the SD card directly to the 3.3v output on my Arduino Mega it works fine. However my GPS also requires the 3.3v and when I wire the two to a breadboard the GPS works fine but the SD card does not initialize.

I assume this error is due to the SD card not being able to draw enough power. I have tried to splice the same wire from the mega to both devices and had postiive results for a few minutes, but lost it when I rebooted (I didn’t fry anything, I have tried them separately since and had postiive results).

Any help on how to wire this up would be appreciate.

2

Maybe it’s drawing too much power for the regulator? From memory, the current drawn by an SD card can be 10s of milliamps when writing, and GPS modules can be pretty high too.

If you have an oscilloscope, try monitoring the voltage. If it drops excessively at certain times (e.g. startup), one of more devices will “brown out”. If these periods are very brief, adding a capacitor to the 3.3V line should help. I can’t remember what regulator the Arduino uses, but worst case you may need to replace it or supplement with another 3.3V regulator.