Is there a way to play sounds from an Arduino without using a sound shield?
I helped someone with a similar question. The results are in my github repo at https://github.com/linhartr22/count. This example uses the PWM library and includes a reference to the article I used to learn how to convert audio files to MP3 with proper settings for the PWM libary. It plays audio through an 8 ohm speaker or a piezo buzzer connected directly to the Arduino.