ESP32 NFC Audio Player – PCB Audit + Firmware Completion (No Hardware Prototype)

I’m looking for an experienced embedded systems / hardware engineer to take over an existing ESP32-based NFC audio player project .

⚠️ Important clarification
The physical PCBs are not currently available.
I am looking for an embedded systems developer to review and complete an existing ESP32 NFC audio player project.

The project already includes:
• PCB design files (Gerber, BOM, Pick&Place, STEP)
• Partial firmware for ESP32
• NFC reader and microSD audio architecture

IMPORTANT
This project is strictly limited to design audit and firmware work only.

No PCB manufacturing, hardware assembly, or physical prototype is required.

Project Scope

Phase 1 – PCB & Firmware Audit
• Review existing PCB design files
• Review current firmware structure
• Identify potential blocking issues
• Suggest minimal PCB corrections if required

Deliverable:
Short written audit report describing findings and recommended changes.

Phase 2 – Firmware Completion
Complete the ESP32 firmware to support:

• NFC UID detection
• UID → MP3 mapping
• MP3 playback from microSD
• basic audio playback control

Deliverables:
• working firmware source code
• documentation explaining the code structure

Constraints

• Budget: 100 € fixed
• No hardware prototype required
• No PCB ordering or assembly
• Communication and clear documentation required

Skills Required

• ESP32 development (Arduino or ESP-IDF)
• NFC integration (RC522 or PN532)
• microSD audio playback
• Embedded C/C++
• Experience debugging embedded systems

Required Skills

ESP32 firmware (FreeRTOS or Arduino)

NFC (RC522 / PN532)

SD card audio playback

Debugging on real hardware

Clear communication