Pedestrians distracted by smartphones are easy to meet with various dangers when crossing or walking on the street, such as the obstacles on the sidewalk (e.g., temporary parking and road repairing).

Here is a design for a full-featured motor shield that will be able to power many simple to medium-complexity projects. 2 connections for 5V 'hobby' servos connected to the Arduino's high-resolution ...

Abstract: A vision-based obstacle detection system for small unmanned aerial vehicles ... The feasibility of this approach is demonstrated by using the vision output to steer a small unmanned aircraft ...