Request for Quote – Residential Gas Safety Device GSM-Only (SMS + Voice Calls) + Auto 220V Fan – No App, No WiFi Hi, I’m looking for a skilled embedded engineer or small team to build a solid, production-ready gas safety device for homes – focused on stopping CO/gas poisoning at night while people sleep. It must be safe, reliable, and ready for small manufacturing (CE-friendly design). How it works (100% offline via GSM/SIM): • Monitors multiple high-reliability sensors continuously • Smart logic (optional TinyML) to avoid false alarms • On real danger: • Loud buzzer + red LED • Auto-activates 180–250V AC fan to vent toxic air • Sends SMS to 2–3 numbers: “GAS ALARM! High CO – ventilating. Address: …” • Makes auto voice calls (repeats if no answer): “Emergency gas alarm at [address] – check now!” • Fan stays on until safe • Fail-safe: fan defaults ON + alerts on fault/power issue • Optional daily “system OK” SMS Sensors I want (upgrade from cheap MQ types for better accuracy/stability): • CO: Electrochemical sensor (e.g., Citytech 4CO or Honeywell/Figaro style, 0–500 ppm, high precision, low drift) • Combustible gases (methane/LPG/propane): Catalytic bead or Infrared (IR) sensor (e.g., Figaro TGS or Senseair-style, better long-term reliability) • Toxic gases / air quality: Electrochemical or metal-oxide high-grade (e.g., Winsen or SPEC Sensors for NH3, NO2, etc.) • Smoke/fire: Photoelectric smoke sensor + IR flame detector • Temp/humidity: SHT series or equivalent (for compensation) You can suggest exact models/brands if better or more cost-effective. What I need: 1. Schematic + production PCB (4 layers preferred, strong AC isolation) 2. ESP32 firmware (FreeRTOS): sensor handling, logic, fan control, GSM SMS + voice calls 3. TinyML (TFLite Micro) preferred for false-alarm reduction 4. Industrial 3D enclosure (wall/ceiling mount, good airflow) – STL/STEP + renders 5. Manufacturing package: BOM with prices, assembly/test/calibration guide, docs Safety musts: • Full galvanic AC isolation • Surge/EMI protection, fuses, optocouplers • Fail-safe design • CE-ready (LVD/EMC) Deliverables: • KiCad files + Gerbers/Pick&Place/BOM • Clean firmware • Working SMS + auto calls • TinyML model (if included) • 3D files + renders • Detailed BOM, test guide, docs Quote fixed price (preferred) with breakdown: • Hardware/PCB • Firmware + GSM • TinyML (optional) • 3D + docs • Total Also share: • Estimated weeks • Main milestones Who fits: • Strong ESP32 + AC safety/isolation experience • SIM800L with SMS + voice calls done before • TinyML bonus Apply with: • Links to similar projects (ESP32 + GSM + AC/sensors) • Quick note on AC isolation + auto calls approach • Timeline + fixed quote Serious proposals only – this is for real home safety and could save lives. Thanks! Looking forward to your quote.