This quadruped robot project is a modification of the Spider Robot project on Thingiverse: 
https://www.thingiverse.com/thing:1009659

The modifications include a change to the upper body STL file to accomodate a Parrot AR Drone 2.0 battery, and a different set of electronics were used. This quadruped uses an Arduino Mega 2560 (clone) with a SainSmart Mega Sensor Shield v2.0 and is powered by a Hobbyking YEP 20A HV (2~12S) SBEC power supply. A HC-SR04 ultrasonic range module and IR obstacle module from a sunfounder.com sensor kit are used for obstacle avoidance. The project also integrates a HC-06 Bluetooth module to send and receive data and commands. Currently, the Arduino is ziptied to the top of the chassis. I plan to design a deck that will mount on the upper body piece to cleanly hold the Arduino and obstacle avoidance sensors. 

The modified source code and a modified upper body to accomodate a Parrot AR Drone 2.0 battery are available on GitHub:
https://github.com/jlverhagen/Quadruped-Robot

A summary of code modifications to make the quadruped work with an Arduino Mega 2560 and the sensors and Bluetooth module:

• Add HC-SR04 ultrasonic range module (echo=pin 15, trigger=pin 16)
• Add IR obstacle module (from sunfounder sensor kit) (pin 17)
• Add HC-06 Bluetooth module to Serial1 (pins 18 an 19)
• Moved last servo from pin 13 to pin 14 to avoid pin 13 LED conflict
• Replace demo code in loop and integrate 3 operating modes: demo, remote control, and auto.

The quadruped robot can be controlled via a terminal emulator over a Bluetooth connection. To do this, I use the BlueTerm app on my Android smartphone and tablets.