This article continues a series about building a DIY digital audio recorder. Inspired by this microcontroller audio project [via], I set out to build a simple digital recording device. I chose Texas Instrument's MSP430 microcontroller for this project because it's fast (16 MHz), it's cheap ($1), and it's very low power. Read the first part, the second part, and the third.
In the first few segments I developed a digital audio recorder prototype that plays raw audio files from an SD card. This time we finish up the introductory segments by recording audio to the SD card. Before the audio can be recorded by the microcontroller, it has to be prepared by a small amplifier. Read on to learn more about working with microphones and recording audio with a microcontroller.