This Ultrasonic scanner is made by Devantech that has a longer range than the SRF04.
This great sonar ranger from Devantech offers an amazing wide range from 3cm to 6m. Unlike the SRF04, the SRF08 is interfaced using the IIC/I2C bus. There is an additional photocell sensor on the front of this detector.
Roboteq's RoboPads charging contact system offers a precision, high current charging solution for mobile robots and Automated Guided Vehicles (AGV).
Autonomous patrol and security platform. Options for object detection, automated pathing, indoor/outdoor functionality are available.