With the use of ultrasound the LEGO Mindstorms EV3 & NXT Ultrasonic sensors could detect the distance to an object. You can use it in many different ways most of them very interesting and fun. Some of them a little more challenging, but rewarding.
The new Spy is a robot with tank treads, which uses one medium motor to turn three things at once. That is achieved by a gear system. Simultaneously the robot turns its two hands up and down, but in opposite directions and its head - left and right.
The robot moves with the help of two tank treads, attached to two Large EV3 Motors.
LEGO Mindstorms EV3 Robot designed for a Folk Race competition. This robot has three Ultrasonic Sensors. Follow the building instructions and at the end, you would have a very basic robot with tank treads that you could directly use.
The building instructions are for a robot that kind of looks like the Spy Bot but it has treads instead of wheels. Like a Tank. Tank Spy Bot. Treads are always funny and you could use the robot chassis base to extend with additional attachments and tools.