Contact person: Business Client

Phone:Show

Email:Show

Location: Bleasby, United Kingdom

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"I’m building a compact DJ controller around the ESP32-S3 and need a developer who can turn my feature wish-list into a functional prototype.

Core features I want implemented
. playing music tracks with spotify api and apple music api
• Track mixing handled on-board, with smooth cross-fade and basic EQ.
• Lighting control driven by the same ESP32-S3 so light cues stay perfectly timed with the music.
• ElevenLabs TTS playback triggered from the set list (think quick vocal stingers between tracks).
• Custom wireless audio output that streams over ESPNOW rather than classic Bluetooth.
• A browser-based control panel (no native app) that lets me load tracks, mix, fire effects and tweak lighting from any phone or laptop on the same network.

What I expect as deliverables
1. Firmware source (Arduino or ESP-IDF—your choice) that boots cleanly on the ESP32-S3, exposes a WebSocket/HTTP interface, and manages the audio, lighting and TTS tasks concurrently.
2. A lightweight, responsive web UI with play/pause, cross-fader, cue points, lighting presets and a button to trigger TTS lines.
3. Proof-of-concept code for the ESPNOW audio link, including a simple receiver sketch so I can test latency and range.
4. Basic documentation: pin map, build instructions, and a short README explaining how to add new tracks or ElevenLabs keys.

If you’ve worked with real-time audio on microcontrollers, ESP-IDF, or custom wireless protocols, I’d love to see a quick example. Let’s iterate rapidly, starting with a working skeleton and adding polish once the core pipeline is solid.

See the full desription below:
Hardware Structure Overview
Custom PCB integrating the ESP32-S3 as central SoC, with raw chips for peripherals. Use I2S for audio I/O, SPI/UART for controls. Storage: microSD or SPI flash for OS/cached files. Power: 5V input with LDOs (e.g., AMS1117 for 3.3V). Software: ESP-IDF for low-level, or Arduino for prototyping; download/playback via HTTP and mpg123.
1. Networking for Server Access (Requirements 1-3)

WiFi: Integrated in ESP32-S3 (802.11b/g/n, up to 150 Mbps). No extra chipset needed; design PCB antenna or add [login to view URL] connector for external (~$0.50). Handles track/TTS MP3 downloads.
4G Fallback: Qualcomm MDM9207 chipset (raw modem IC, ~$10-15 in bulk; used in Quectel EG25-G). This is a Cat 4 LTE baseband processor with integrated RF transceiver.

Integration: Connect via SDIO/USB to ESP32-S3; requires external SIM holder, antennas (diversity/MIMO), and PMIC (e.g., for power sequencing). Use AT commands for control.
Why raw? Cheaper than Quectel EG25-G module (~$40-50 retail); alternatives like Cavli CQ20 module (~$30-40, if you accept modules) or MediaTek MT2625 (~$8-12, but NB-IoT focused, lower speed).
Failover: ESP32-S3 software handles switching (e.g., via lwIP stack).
Antenna: External SMA/[login to view URL] for main/diversity (~$1-2 each).



2. Wireless Audio Output to Speakers (Requirement 4: Direct, Not BLE/WiFi)

Technology: Use Espressif ESP32 (raw chipset, ~$3-5) or Nordic nRF24L01+ (raw 2.4 GHz transceiver IC, ~$1-2) for a custom direct RF protocol. Avoid SKAA (expensive modules, ~$250/transmitter).

Preferred: ESP32 with ESPNow: ESPNow is direct peer-to-peer (uses WiFi radio but bypasses network; meets "direct" criteria). Feasibility: Projects like ESPNowAudio library show 16-48 kHz mono/stereo streaming with ~20-50 ms latency (acceptable for DJ). Bandwidth: Up to 1-2 Mbps, enough for compressed MP3 (128 kbps) or raw PCM (at lower quality). Examples: GitHub repos for ESP32 voice streamers (e.g., [login to view URL]); adapt for multi-speaker broadcast (up to 20 receivers).

Integration: One ESP32 as co-processor (SPI to main SoC), streams mixed audio (I2S input). Receivers: Cheap ESP32 boards (~$5) in speakers.
Pros: Low latency, reliable in clean environments; free protocol.
Cons: 2.4 GHz congestion; implement packet loss handling.


Alternative: nRF24L01+: Raw 2.4 GHz GFSK transceiver (250 kbps-2 Mbps). Use RF24Audio library for streaming (8-16 kHz mono, ~50-100 ms latency). Examples: Arduino walkie-talkie projects; adapt for multi-channel (up to 4 stereo via multiple chips).

Integration: SPI to ESP32-S3; custom firmware for audio packetization/compression (e.g., ADPCM to fit bandwidth).
Range: 50-100m line-of-sight; add PA (power amp) like RFPA0133 (~$2) for extension.


For 8 speakers (4 stereo): Broadcast mode; one transmitter chip handles all (nRF24L01+ supports multi-receive).
Compression: Software on ESP32-S3 (e.g., OPUS library) to reduce data rate.



3. Wireless DMX for Lighting Control (Requirement 5)

Chipset: Nordic nRF24L01+ (~$1-2). Raw 2.4 GHz transceiver for custom DMX protocol.

Integration: SPI to ESP32-S3; generate DMX packets (e.g., via OLA library ported to ESP-IDF) and transmit. Receivers: nRF24L01+ in lights.
Why? Cheap, low latency (<5 ms); examples like Arduino wireless DMX projects. Alternatives: LumenRadio CRMXchip (~$10-15, if available raw), but nRF is cheaper.
Channels: Up to 512; broadcast to multiple receivers.



4. Wireless Microphone Input (Requirement 6: 1-2 Mics)

Chipset: Nordic nRF24L01+ (~$1-2 per mic/receiver pair) or similar 2.4 GHz transceivers like CC2500 (~$1).

Integration: Transmitter: nRF24L01+ + mic preamp (e.g., SSM2167 IC, ~$2) + ADC (e.g., PCM1808, ~$2). Receiver: nRF24L01+ outputs to ESP32-S3 I2S/ADC for mixing.
Feasibility: Low-quality audio (8-16 kHz mono) with ~20-50 ms latency; examples from RF24Audio library. For 2 mics: Multi-channel packets or separate frequencies.
Range: 30-50m; digital for noise rejection.



5. In-Built Reverb for Karaoke (Requirement 7)

Chipset: Spin Semiconductor FV-1 (~$10-15, SOIC-28). Single-chip DSP with built-in ADC/DAC and reverb algorithms.

Integration: Analog path between mic input and ESP32-S3; control via I2C/SPI. Programmable with custom effects; low power (50 mW).
Why? Very cheap raw IC; no software overhead if hardware-accelerated. Software fallback: ESP32-S3 with LADSPA plugins (but higher latency).



6. ESPNow Interface for Pub Quiz Buttons (Requirement 8)

Integrated in ESP32-S3: Native ESPNow support (2.4 GHz, 100m range).

Integration: Main SoC handles; receive button presses (first-to-answer with timestamps) via ESPNow from cheap ESP32 buttons (~$3 each). Supports dozens without interference.
No extra chipset needed.



Additional Considerations

Audio Pipeline: ESP32-S3 decodes MP3s (via Helix library), mixes with mics (add reverb via FV-1), outputs to ESPNow/nRF transmitters. Use low-latency mode (e.g., 48 kHz, small buffers) for <50 ms end-to-end.
I/O: GPIO for buttons/LEDs; optional TFT via SPI for UI.
Power: Use PMIC like AXP192 (~$2) for management; battery-friendly.
Challenges: 2.4 GHz band overlap (WiFi, ESPNow, nRF, mics)—use channel hopping. Audio quality with raw chips may be lower (e.g., 16 kHz vs. 48 kHz); test compression. Interference: Add shielding/PA.
Cost Estimate (BOM, 100 units): ESP32-S3 (~$4) + nRF24L01 x3 (~$6) + FV-1 (~$12) + MDM9207 (~$12) + passives/antennas (~$10) = ~$45-60 total (vs. $100+ with modules).
Prototyping: Use dev boards (e.g., ESP32-S3 devkit ~$10) and breakout boards for chips. Libraries: RF24 for nRF, ESP-IDF for ESPNow/audio.
Development Tips: Start with Arduino sketches for ESP32 (e.g., ESPNow audio examples from GitHub). For 4G, use Qualcomm docs for MDM9207 integration.

This raw-focused design cuts costs while meeting requirements. If any part needs more details (e.g., schematics for nRF audio), let me know!" (client-provided description)