Vex Go Robotics kit
The Vex Go kit is for upper elementary - middle school. It comes in 2 boxes with optional base pieces. Students follow directions to build various robots in a lego-like way and then code them to perform. 4 sensors are included to allow the robots to interact with the environment.
This robot is the flop bot. It takes about 20 minutes to build and just a few minutes to program.
It controls a single motor with code to move it forward.
By adding a distance sensor it can be programmed to stop when it gets close to an obstacle.