Copy the GPIO settings for the ECHO and TRIGGER pins as well as the servo setting from the picar-obstacle-avoid.py file
Copy the measure function from the picar-obstacle-avoid.py file
Copy the pwm.set_pwm function calls for the servo from the picar-obstacle-avoid.py file
Copy the ob_range variable from the picar-obstacle-avoid.py file and use it to determine if there is an obstacle that the PiBot needs to avoid
Include debugging prints to help troubleshoot if the distance measured doesn't seem to be working
Make the changes to the intersection decision logic to sense for obstacles and react to any obstacles that are in the path
It may be easiest to only take a sonar measurement after making a decision (and turn if necessary) at an intersection. If there is an obstacle then the PiBot will need to undo the decision (and turn).
Bonus points if you include moving the sonar sensor in the PiBot's “Happy Dance” when it reaches the end of the maze

Return to Challenge 2
"“Worthy are you, our Lord and God, to receive glory and honor and power, for you created all things, and by your will they existed and were created.” - Revelation 4:11"