NFC-Based Children's Audio Player Development

Project Description I am developing an educational NFC-based audio player for children (ages 2–7). The concept is simple: a child places an NFC figurine on the box, and an associated audio story is played. The project already has a custom PCB prototype (ESP32-based) and early firmware work, but I am looking for a new freelancer to take over, audit the existing work, and complete a fully functional prototype. This is a serious product project, not an experiment. What Already Exists: I will provide a structured project folder including: Custom PCB files (Gerber, BOM, Pick & Place, STEP file) PCB size: 80 × 80 mm ESP32-based design NFC reader integrated MicroSD slot Battery charging circuit (Li-ion) USB-C Speaker output + headphone jack NFC detection already demonstrated via serial console (video available) Partial firmware work (NFC UID detection) Your Mission Phase 1 – Audit & Validation Review existing PCB design files Review firmware status Identify what works and what needs fixing Confirm if PCB can be used as-is or needs revision Phase 2 – Firmware Completion Complete ESP32 firmware: NFC tag reading Mapping NFC UID → audio file MP3 playback from microSD Speaker + headphone output Basic button handling (play/pause, volume) Ensure stable and testable behavior Phase 3 – Functional Prototype Guide or validate final wiring (speaker, battery, SD) Provide clear testing instructions Deliver: Working firmware Demo video of the prototype in action Clear documentation Important: No upfront hardware purchases at your own expense. All costs must be approved before any spending. Deliverables Firmware source code Clear setup & testing documentation Demo video showing: NFC tag detection Audio playback Confirmation of prototype readiness for enclosure integration Budget $50–150 USD, depending on experience and scope after audit (Milestones only – escrow-based) Ideal Freelancer Profile Strong experience with ESP32 NFC (RC522 / PN532 or similar) Audio playback (I2S / DAC / SD card) Comfortable reading existing PCB designs Clear communicator Professional and transparent with costs Portfolio or examples of similar electronics projects required Nice to Have (Not Mandatory) Experience with children’s electronic products Understanding of low-power / battery devices How to Apply Please include: Brief introduction Relevant experience (ESP32 / NFC / audio) Examples or portfolio Your approach for taking over an existing project Physical Prototype & Shipping (Mandatory) The final deliverable of this project includes at least one fully assembled and tested physical PCB prototype. This means: The freelancer must either already have the assembled PCB or Receive it, assemble missing components if needed, test it, and Ship at least one fully working prototype to me at the end of the project. Shipping of the physical prototype is mandatory and must include: 1 fully functional PCB Any remaining PCBs from the initial batch (if applicable) Proper packaging Shipping costs will be paid by me, but must be discussed and approved in advance. No milestone will be released without: Video proof of the working physical prototype Confirmation of shipment (tracking number) If you cannot handle physical assembly and shipping, please do not apply. Required skills: ESP32 embedded development NFC / RFID (RC522, PN532, UID reading) Embedded audio (MP3 playback, I2S/DAC, amplifier, speaker) Firmware development & debugging Hardware testing on real PCBs Nice to have: PCB review & BOM validation Battery management (Li-ion) Experience with physical product prototyping Note This project already went through one iteration with another freelancer. I am looking for someone reliable, structured, and professional to move forward cleanly.

ID do Projeto: 40130487