SynthBoard: Audio Synthesizer

SynthBoard is an audio synthesizer designed to bring professional-grade audio generation and waveform manipulation to an accessible, open-source platform. The device features a 4x4 button interface, individually addressable RGB LEDs, and 8 potentiometers for real-time control of waveform parameters and audio effects.

At its core, the SynthBoard uses the STM32F407 microcontroller, using its built-in audio DAC and GPIO capabilities. I implemented a button matrix with ghosting prevention via diodes. Additionally, the RGB LED lighting effects were achieved using WS2812B LEDs in a daisy-chain configuration, allowing individual control with minimal wiring.

The potentiometers were integrated with the STM32 ADC channels to provide precise control over parameters such as waveform type, harmonic content, and ADSR envelope settings. Each knob directly adjusts key synthesis features like attack, decay, sustain, release, and low-pass filter cutoff frequencies.

On the software side, I developed modular C++ classes for components like oscillators, ADSR envelopes, and low-pass filters. The system supports sine, square, triangle, and sawtooth waveforms, with additive synthesis principles enabling rich harmonic generation. Inline functions, integer arithmetic, and bitwise operations were used to optimize performance for real-time audio processing on resource-constrained hardware.

The entire design, including the enclosure and components, was modeled and validated in Fusion360. Key elements like button clamps, LED prisms, and potentiometer housings were 3D printed with precision for durability and compatibility.