In this paper we describe our approach to teaching applied digital signal processing (DSP) using freely-available software and inexpensive off-the-shelf hardware components. The pedagogical framework is built around simple real-time audio processing algorithms that provide immediate and engaging feedback to the students. At the same time, our end goal is to build a learning module that can be easily reproduced by fellow instructors and used in our Massive Open Online Course (MOOC). We use Python for the initial algorithmic prototyping and then transition to a hardware implementation using an STMicroelectronics' Nucleo-64 core with Adafruit I/O breakout boards. We employ modern documentation tools based on Git and Markdown in order to share the material and the exercises, allowing students and educators to access, reproduce, and contribute changes to the content.