RP2350 Birdsong Synthesizer

Built with two teammates for Cornell ECE 4760, this interactive synthesizer generates birdsong-like calls on a Raspberry Pi Pico 2 using direct digital synthesis. A slide potentiometer controls frequency across a programmed 0–10 kHz range, while a matrix keypad supports recording, playback, and composition.

I implemented DDS generation, the timer interrupt and timing instrumentation, and ADC integration for the potentiometer. I also contributed to system bring-up, debugging, oscilloscope measurements, and final report integration.

Our system sends synthesized audio to an MCP4822 DAC over SPI and supports nine recording slots with approximately tenfold accelerated playback. Oscilloscope measurements captured an instrumented interrupt duration of approximately 2.09 microseconds within a 20.2-microsecond interrupt period.

We compared synthesized calls with a northern cardinal reference using spectrograms. The system produced repeatable birdsong-like sequences, although Merlin Bird ID did not recognize the synthesized calls during testing.

• Implemented DDS with a 32-bit phase accumulator and sine lookup table.
• Integrated ADC-based potentiometer control over a programmed 0–10 kHz range.
• Instrumented and measured audio interrupt timing with an oscilloscope.
• Helped integrate and test recording, accelerated playback, and sequence composition.

Synthesizer Hardware

Raspberry Pi Pico 2, slide potentiometer, matrix keypad, and MCP4822 DAC.