After several failed attempts with my setup, I decided to try something new—integrating the Bela Board into the signal chain. Bela, with its superior audio processing capabilities and real-time performance, seemed like the perfect candidate to handle the microphone signal and drive the PAM8403 amplifier. But, as much as I wanted this to work, I quickly realized that Bela might not be my cup of tea.
This time, I started by powering the MAX9814 module with a stable 12V supply, regulated through an LM7812 voltage regulator. Since the PAM8403 can only handle 5V, I had to carefully split the power:
- I used a voltage divider circuit with two resistors to step down the 12V supply to 5V for the PAM8403.
- While this was a temporary hack, the power supply seemed stable enough to proceed.
Next, I introduced the Bela Board into the setup. Bela’s 3.5mm audio output provided a convenient way to interface with the PAM8403. The idea was to process the microphone signal through Bela’s ADC (audio input), then output the processed audio to the PAM8403 and finally to the speaker.
But here’s where things got tricky. The Bela output, connected via a 3.5mm audio cable, had to interface with the breadboard and the PAM8403. I spent hours trying to debug the connections, ensuring the signal paths were clean and the power was stable. Despite all this effort, no sound came out of the speaker—not even a crackle or pop.
At this point, I had to ask myself: was this failure a result of my setup, or was it something about the Bela Board itself? Objectively, Bela is a fantastic tool:
- Its real-time audio processing capabilities are far superior to Arduino.
- The programming environment is straightforward and optimized for sound-related projects.
But for some reason, I just couldn’t connect with it. Perhaps it was the higher cost, which felt hard to justify compared to Arduino. Maybe it was the unfamiliar workflow, or maybe it was just me being stubborn. Regardless, I found myself disliking Bela on a personal level. Its strengths were undeniable, but it didn’t feel like the right fit for my project.
Reflecting on this experiment, I suspect the problem might have been the way I connected Bela’s 3.5mm output to the breadboard and PAM8403:
- The breadboard isn’t designed for handling audio cables, and the connections likely introduced signal loss or noise.
- It’s also possible that Bela’s output impedance wasn’t well-matched with the PAM8403 input, resulting in no signal amplification.