Book Image

Raspberry Pi for Secret Agents - Third Edition

Book Image

Raspberry Pi for Secret Agents - Third Edition

Overview of this book

This book is for all mischievous Raspberry Pi owners who’d like to see their computer transform into a neat spy gadget to be used in a series of practical pranks and projects. No previous skills are required to follow along, and if you’re completely new to Linux, you’ll pick up much of the basics for free. We’ll help you set up your Raspberry Pi Zero, Raspberry Pi 2 and Raspberry Pi 3 and guide you through a number of pranks and secret agent techniques that are so inconspicuous yet high on mischief. You’ll learn how to configure your operating system for maximum mischief and start exploring audio, video, or Wi-Fi techniques. We’ll show you how to record, listen, or talk to people from a distance and how to set up your own phone network. Then, you’ll plug in your webcam and set up a motion detector with an alarm and find out what the other computers on your Wi-Fi network are up to. Once you’ve mastered the techniques, we’ll combine them with a battery pack and GPS for the ultimate off-road spy kit.
Table of Contents (7 chapters)

Distorting your voice in weird and wonderful ways

Tired of your own voice by now? Let's make it more interesting by applying some cool SoX effects!

SoX comes with a number of sound effects that can be applied to your audio and optionally saved. Some effects are suitable to use on your live voice while others only make sense when applied to already recorded files.

To see a list of all the possible effects and their parameters, use the following command:

pi@raspberrypi ~ $ sox --help-effect=all | less

To apply an effect, specify the effect followed by any parameters after the output file or device.

In this example, we'll start a monitoring loop on the Pi and apply a reverb effect to our voice live as it plays back through the speakers:

pi@raspberrypi ~ $ sox -t alsa plughw:1 -d reverb

If you receive "under-run" warnings from ALSA whenever you run sox, these can be safely ignored.

How about that? Sounds like we're stuck in a cave. Let's see what parameters the reverb effect takes: