Leap Motion you can get over here:
Step 1: Step 1 Syma X1 Remote Control:
First you have to add two 2.5K resistors as shown in the circuit picture.
Next thing you have to do is to short three points as shown in the picture.
Step 2: Step 2 Digital to Analog Cards:
2. Connect the SDA output from each of the 3 A/Ds together to the arduino's analog 4 input (The GREEN wires on the circuit picture)
Step 3: Step 3 Flip Button:
Step 4: The Code (C# + Ardunio)
(I used google drive to upload it).
For more deep understanding I used 123D to make the circuit in this link you can find the project
I made alone the schematic for the remote control and the MCP4725 D2A, 123D GUI is very simple and very helpful !