Multitasking with Raspberry Pi

Multitasking and multiprocessing have become a very important topic in microcontroller-based systems, namely in complex commercial, domestic, and industrial automation applications. As the complexity of projects grows, more functionalities are demanded from the projects. Such projects require the use of multiple inter-related tasks running on the same system and sharing the available resources, such as the CPU, memory, and input-output ports. As a result of this, the importance of multitasking operations in microcontroller-based applications has grown steadily over the last few years. Many complex automation projects now make use of some form of a multitasking kernel.

This book is project-based and its main aim is to teach the basic features of multitasking using the Python 3 programming language on Raspberry Pi. Many fully tested projects are provided in the book using the multitasking modules of Python. Each project is described fully and in detail. Complete program listings are given for each project. Readers should be able to use the projects as they are, or modify them to suit their own needs.

The following Python multitasking modules have been described and used in the projects:

• Fork
• Thread
• Threading
• Subprocess
• Multiprocessing

The book includes simple multitasking projects such as independently controlling multiple LEDs, to more complex multitasking projects such as on/off temperature control, traffic lights control, 2-digit, and 4-digit 7-segment LED event counter, reaction timer, stepper motor control, keypad based projects, car park controller, and many more. The fundamental multitasking concepts such as process synchronization, process communication, and memory sharing techniques have been described in projects concerning event flags, queues, semaphores, values, and so on.