If you have an android device, you probably can plug in a USB OTG cable and then a memory card into the cable. This allows your device to use the memory card as required. But wouldnt it be great if you could do the same but without the USB OTG cable. Well that soon will be a reality.
Check out this kickstarter project that aims to create a microsd reader that can plug directly into your device.
Very cool and I hope it is a success.
