The Dynamixel AX-12A Smart Serial Servo from Robotis is the most advanced actuator on the market in this price range and has become the defacto standard for the next generation of hobby robotics. The Robotis AX servo product line features a simple, and robust, TTL level communication protocol. Over a single TTL signal line you can daisy chain several servos and position of several servos independently and read back their positions.
Servo / Sensor cables for Dynamixel Servos. Set of 25. Made by Robotis.
From Robotis, the CM-2+ is the controller board used to control the Dynamixel DX-series, RX-series servos that support RS-485 and AX-series servos which support TTL level.
The GPS 18x is an OEM, high-sensitivity GPS sensor for use in automotive, fleet vehicle, and electronics applications that require a small, highly accurate GPS receiver.
Waterproof ultrasonic distance sensor. This sensor can be used for collision detection in your project.