This Audio Alert box is placed between an audio source and an audio consumer such as an FM transmitter or amplifier. When the alert box wirelessly receives an encoded message, it breaks into the audio stream from the source and plays the mp3 sound clip related to the message received.
See the original Audio Alert description for more: https://www.thingiverse.com/thing:2754869
This new version uses different components and is designed around a finished SMD PCB.
This 2nd version of the Audio Alert project was originally designed to support the 2nd version of the Dust Collector Full board that uses the same transceiver (See https://www.thingiverse.com/thing:2657033). I decided to make the board design somewhat extensible. All of the unused MCU pins have been brought out to the edge of the board for future use along with a dedicated I2C connector to allow for a future display and/or keyboard, etc..
The sound quality of this board is better than the original board. The original board uses a generic analog switch rather than an actual audio switch as used in this new design.
For detailed build instructions see https://www.instructables.com/id/Audio-Alert/
Prints: I printed both at, 20% fill, no support.