This is a simple robot project using 3D-printed parts and an Attiny85. It is controlled using a TV remote but can also drive by itself using an ultrasonic sensor.
More Information: http://coretechrobotics.blogspot.de/2015/12/attiny-canbot.html

Let's make Robots: http://letsmakerobots.com/robot/project/attiny-can-robot

https://www.youtube.com/watch?v=ykMH8ZPQNBU

EDIT: Corrected the circuit diagram (Attiny85 was upside down)