How to Play Audio on Arduino + Debug

This is a way too long tutorial on how to play medium quality audio files on an Arduino. I remember myself starting and what was supposed to be fun development, often times proved to be frustrating error checking. I wanted to make this explanation as complete as I could to help out everyone who might run in to some trouble. More importantly though, I am hoping to help build a more general understanding of the concepts behind this project. Learning how and why it works is vastly more important than just to play a song.

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You can hear popping sound out the beginning and the end of playing. This is known by the TMRpcm developer and supposedly solved in most cases. See the discussion here:
https://forum.arduino.cc/t/tmrpcm-wav-file-player-noisy-sound-before-and-after-playing-a-wav-file/174808/3

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Talking teddy video
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https://youtu.be/3Yvxd4ueedg

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Project files (including schematic):
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https://github.com/Make-It-Happen-DIY/arduino_audio/tree/main

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Wav converter
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https://audio.online-convert.com/convert-to-wav


00:00 -- Introduction
01:07 -- PWM background
02:00 -- Circuit assembly
03.07 -- Amplifier background
04:30 -- Back to circuit assembly
06:29 -- Code
10:35 -- Audio file conversion
11:56 -- Power up
13:17 -- Troubleshooting