Building a robot is a project well-suited to the Arduino. Building a robot which can be controlled wirelessly via a smartphone is a logical follow-on project. Building an autonomous robot follows, but making the leap between getting a motor to spin on demand and programming your very own 'smart' robot can be a daunting step to take.
For anyone interested in getting started with Arduino robotics, maker Azhar Muhammed has published his second Instructable - following his earlier pipe-based robot project - and it's a great way to break into the subject. Despite being made to a low budget and using readily-available parts - the body of the motor being a plastic box more typically found in the kitchen, for example - Azhar's project covers all the features of a basic two-motor robot in an easy-to-follow manner.
Where many projects would be content to call a robot 'finished' when it can move in a straight line, Azhar's introduction is a little more ambitious: the inclusion of the popular HC-05 Bluetooth module means the robot can be controlled from a smartphone or tablet, while an HC-SR04 ultrasonic sensor gives the robot enough information about its surroundings to perform autonomous tasks including obstacle avoidance, wall following, and maze solving.
Despite this apparent complexity, Azhar's robot is genuinely accessible to the beginner. No specialist tools are required beyond a drill and a glue gun, there is no expensive chassis holding everything together, and all the parts are easily purchased from local or international suppliers at a very low cost.
What about making your own robots? It's a really cool thing. But if you don't know where to start, then this Instructable is best for you. In this tutorial I am going to show how to make an Arduino robot with different functionalities. We can learn the use of different programs for different functions, mainly a smartphone controlled robot with obstacle avoider, wall follower or maze solver robot, or you can also make it for a single function.