I recently built the Baby R2 (BB-R2) from Michael Baddeley. This build was great fun and very "EZ" as the 3D print files are well designed to work without supports. The build was for my great nephew who wants to become and aerospace engineer. When I was a youngster Star Wars inspired me to want to be an electrical engineer and build robots. I built up the robot app in ARC and made a mobile version for his IPAD. 
Programming
One of the most fun parts of the build was developing the mobile interface using Synthiam by ARC. The first thing I did was to create the backdrop for control screen in which I would put all of the controls on top of. Here is the backdrop I developed:
Next I used the interface builder to add the controls on top of the background:
There are many R2-D2 sounds available to download on the Internet. I brought several of them into the build. The joystick of course controls the movement of R2. The dome rotates left or right with the arrows on either side of R2' head. The dome will stop rotating by pressing the Radar Eye in the middle of the head. I posted this app as public and called it "BB-R2".
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Parts & Materials
Michael has provided a great set of instructions to build the robot as well including the parts list and STL files. He normally uses RC controls, but I chose EZ-Robot approach. For the build, I used the I/O Tiny, a 7.4V 1000mah LIPO, and a speaker that I took from some broken radio. I used three continuous rotation FS90R servos. Because the maximum voltage for the servos is only 5V and I am powering the IO Tiny with a 7.4V battery, for each servo connection I used a Servo Voltage Regulator for each channel.
Other robots from Synthiam community
Andy's "Lilian" Is Assembled And Running
Animator28's AVA (Advanced Visual Android)
I really need to expand into 3D printing. I get stuck on large things that take forever to complete and miss out on stuff like this.