Add and monitor control sensors

Making sense of the situation, Les Pounder shows us how to use sensors with a robot to get about town!

-  Les Pounder

OUR EXPERT Les Pounder is associate editor at Tom's Hardware and a freelance maker. He blogs about hacks and makes at http://bigl.es.

At the end of part two, we had successfully built our robot from a kit, soldered the motors and tested them using a series of directional commands. To facilitate this, we created our own Python module to make things easier to control and abstract away some of the complexities. In this part, we move on to writing code that takes data from sensors and uses it to give our robot 'brains'.

Sensors, much like our own, provide a means to see and interact with the world around us. We use our eyes to see the world. Robots can see the world around them with OpenCV (Open Computer Vision), which uses machine learning to identify objects and people, and react accordingly. At a more basic level, robots can 'see' using ultrasonic and obstacle sensors. There are so many sensors to choose from it can bewilder even the most seasoned of makers. We've chosen to stick with the most basic forms: infrared, buttons and ultrasonic sensors. The more advanced methods of input and control will come in a future part.

This part can become quite complex - remember, we are working with multiple types of sensors. We will write the code and test each one as we go. We may use them all, or just a few. That is a decision for you. Make your robot as complex or simple as you wish - we will give you the tools and the knowledge to realise it. Start with a single sensor, learn how it works and then apply that knowledge to your build. The online resources have all of the code snippets for you to add to your code, and our robot.py file contains every function for every sensor we create in this tutorial.

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