Why design your own arduino shield
- It's cheap, our stuffs you need only cost 1-2 USD, and it's also easy and fast to build. We are going to a bluetooth adapter, an official one need $19.
- Wiring is annoying, how many times you made wrong wiring..
- It's stackable and you can use again and again without wiring, stacking it also makes it easy to fixed, other arduino shields can also stack and stack again.

BOM
- Break away pin header Male, you can use normal pin header, or the speical arduino pin header
- Break away pin header Female
- Prototype board, 5*7 CM size
- Soldering wires (this may even not necessary)

Step 1: Measure and Soldering

First you have to put the break away pins header into your arduino, and then put the prototype board on top of it. Get correct position, make sure all the pins are connected.
After that, you can soldering and fixed the prototype board with the pin headers below

Step 2: Connector on Prototype Board

Soldering the other connector for the bluetooth module anywhere you want, just make sure it convenient.

You also have to think about how to design the wiring go through well, see the reference pictures. You can also use the metal wires connect the two ends and make the soldering line. I am here using the "flying" wiring, for this simple case.

Step 3: Finish Soldering Wires

Two soldering wires to GND and VCC on bottom, and TXD and RXD to the top, just finish all the wires soldering, and tape it. Of course, you can make it better :D

Done! see the last picture, 00:02:0A:01.... is the bluetooth module