Inspired by this video/OTG, pass to 0:47. Which I couldn't find one to purchase. This L design when plugged in is a bit smaller than a penny. No welding needed! Use (female USB for game controllers, mouse, ect). Designed with a case-on in mind.
You'll need 3 parts for hardware. Micro USB OTG, Micro SD reader, ofcourse Micro SD card and a software of your choice to run it. I don't root so I'm using Nexus Media Importer.
Be safe and wear gloves. You don't want to get hurt for this mod.
Step1: Cut in the middle of the left or right side of Micro USB OTG. Be careful, use glove on the hand to hold it down. (note: the OTG link that i provided is the exact one that I used to mod, but you can find the cheapest parts from Amazon or Ebay, ect.).
Step2: Peel out the inner part of the OTG.
Step3: Cut the part closer to the Micro USB completely off (with wires still intact). Carefully peel the wires to the far end of the USB female. Then cut the rest of the plastic off like in the picture.
Step4: Turn the Micro USB end to make a L shape like in the picture. I used glue gun to clued it together. You can use electrical tape if you like. Enjoy!
**I'm not holding reliable for any injuries or broken parts from this mod, do it at your own risk**
This is the original size of the device when it's plugged in, it's about 3 size of a penny in length.
Version 2 still retained female USB for mouse and game controller or a case in mind.
You'll required soldering, glue gun or electrical tape. (note: this version is a challenge to make. If you think you can solder the wires into the small spaces on micro USB's bins then proceed or you can make version 1 which required no soldering)
Step1: Strip micro USB and female USB completely. (any spare female USB from old devices will do. Make sure you have the right micro USB end like in the diagram if you decided to get a spare)
Step2: Measure the wires as needed from micro USB to female USB. Then pre-cut the outer layer of the wires so you can bend at 90 degree angle with ease when wiring the wire along the sides. (careful don't cut the wires inside). Next, strip a few millimeter from both ends of the 4 wires.
Step3: I suggest to lay the 4 wires on top; along the micro USB and solder it in the pins. (though I didn't realized this obstruction was a big deal until it resulted in a bump on my model when wiring it downward). Curve your stripped end of the wires for easy soldering. A trick I used to solder the wires to micro USB is putting a thin foil paper in between 2 pins. After you're done, remove it and repeat until you're done.
Step4: Lay your micro USB on top of the solder point of the female USB at 90 degree to shape the L. (make sure no metal part of the micro USB touches the female USB sholdering point. You can lay it on top of the female USB but it will add a few millimeter thickness). Follow the diagram to solder all wires to the female USB.
aaaa v.2 when plugged in it's half a size of a penny. You're seeing USB plugged into the OTG with microSD inside.
**Credit to redgreenlaser for diagrams**