This great sonar ranger from Devantech offers a wide range from 3cm to 3m. For further range see the SRF08. The SRF04 is interfaced using the one output line to ping the sensor and an input line to read the echo.
This is the SRF08 Ultrasonic ranger made by Devantech. The Ultrasonic detector can detect from ~4 inches to ~30 feet.
This is the SRF05 Ultrasonic ranger made by Devantech. The Ultrasonic detector can detect from ~4 inches to ~13 feet.
The Dynamixel MX-106T TTL Servo is the newest generation servo from Robotis. Equipped with an ARM Cortex M3 features a PID control algorithm and provides feedback information such as speed, temperature, position and load.
Audio Installation Cable. 6 inch 3.5mm female to RCA male Y Cable