Contact person: Business Client

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Location: Buenos Aires, Argentina

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"Project Description:
I am looking for an experienced embedded audio/DSP developer to design and implement an audio processing firmware based on the ESP32-S3 Audio Front-End (AFE) framework and integrate it with an existing VoIP system running on a Raspberry Pi.

The VoIP software on the Raspberry Pi is already fully developed.
This project focuses exclusively on the ESP32-S3 side, using Espressif’s AFE, and the audio/data communication between the ESP32-S3 and the Raspberry Pi via I2S.

Project Goals:
- Use ESP32-S3 as a dedicated audio processing unit

Implement Espressif Audio Front-End (AFE) features, such as:
- Acoustic Echo Cancellation (AEC)
- Noise Suppression (NS)
- Automatic Gain Control (AGC)
- (Optional / desirable) WakeNet or voice trigger support

Establish bidirectional audio streaming via I2S between:
- ESP32-S3 ↔ Raspberry Pi
- Ensure low-latency, stable audio suitable for real-time VoIP
- System Architecture (High-Level)

Microphone input:
MEMS I2S microphone connected directly to ESP32-S3

Playback reference:
Audio playback stream from Raspberry Pi provided to ESP32-S3 as AEC reference (via I2S)

Processed output:
ESP32-S3 sends filtered/processed microphone audio back to Raspberry Pi via I2S

Raspberry Pi:
Handles SIP/VoIP, networking, codecs, and call logic (already implemented)

Only consumes and provides raw PCM audio over I2S

Scope of Work:
Included:
- ESP32-S3 firmware development
- Configuration and use of Espressif AFE
- I2S audio interface implementation (TX/RX, clocking, sync)
- Audio buffer management and latency optimization
- Clear documentation of:
I2S audio format (sample rate, bit depth, channels)
Build and flashing instructions

Not Included:
- VoIP stack or SIP development
- Raspberry Pi VoIP application changes (minimal or none)
- Hardware PCB design (logic-level assumptions only)

Technical Requirements:
ESP32-S3 (mandatory)
Espressif Audio Front-End (AFE) framework (mandatory)
I2S audio interface (mandatory)
Experience with:
- Real-time audio DSP
- Embedded C/C++
- ESP-IDF
- Audio latency optimization
- Understanding of AEC reference signal handling

Deliverables:
- Fully working ESP32-S3 firmware
- Source code (ESP-IDF project)
- Basic documentation explaining:
Audio flow
Configuration parameters
How to interface with the Raspberry Pi
- Test procedure or example to validate audio flow

Nice to Have
Prior experience with:
- ESP32 AFE / WakeNet
- VoIP or telephony audio pipelines
- Linux audio systems (ALSA / PipeWire)
- Suggestions for improving audio quality or robustness

How to Apply
Please include:
- Relevant experience with ESP32 audio or DSP
- Examples of similar projects (if available)
- Estimated timeline
- Any questions or recommendations regarding the architecture" (client-provided description)