Hi, there, we have lunched a new product and allow me to introduce it to you here. The RTC Data Logger shield (http://http://www.elecrow.com/rtc-data-logger-shield-p-1370.html) can adds storage to your Arduino project. It supports SD, SDHC, or MicroSD TF cards and has a RTC onboard. Use the on-board toggle switch to select the SD card type. And when you want plug a sd card on it, you should select the switch to the right direction.

Furthermore, 3.3v level shifter circuitry can prevent damage to your SD card. You can get example code for both SD and RTC for quickly Prototyping area for soldering connectors, circuitry or sensors. Real time clock (RTC) will keep the time going even when the Ardu is unplugged.