Smart Cooking Thermometer with Auto-Timers Project Overview: I need an Arduino firmware + mobile app for a smart cooking thermometer that starts timers automatically when recipe step temperatures are reached. Hardware Setup (Ready to Code): - Arduino Nano + HC-05 Bluetooth + MAX6675 Thermocouple - Wiring: - MAX6675: Pins D12(SO), D13(SCK), D10(CS) - HC-05: Pins D2(TX), D3(RX) via SoftwareSerial - Power: 5V & GND shared What I Need Built: 1. Arduino Firmware: - Read MAX6675 temperature every second via SPI - Send via Bluetooth: `"TEMP:25.5,77.9\n"` (Celsius,Fahrenheit) - Handle app commands: `"SETTARGET:85,90\n"` (85°C target, 90s auto-timer) 2. Mobile App (Cross-Platform): - Must work on both iOS and Android - Bluetooth connection to "SmartChef-Thermo" - Real-time temperature display with C/F toggle - Recipe step guidance with auto-timers - Key Feature: When temperature reaches target → auto-start step timer - Phone vibration + notification when timer starts/ends Auto-Timer Feature (Core Requirement): ``` Example Flow: 1. Recipe Step: "Heat pan to 85°C for preheating" 2. App sets target: 85°C with 90s auto-timer 3. When temp hits 85°C → app auto-starts 90s countdown 4. Phone vibrates: "Pan preheated! Timer started" 5. When timer ends → vibrates: "Step complete!" 6. Auto-advance to next recipe step ``` IMPORTANT - Recipe System Scope: Phase 1: Simple Pancake Recipe Only - One preloaded pancake recipe with 5-6 steps - Each step has: target temperature + auto-timer + instructions - Example steps: Preheat pan, melt butter, cook batter, flip, etc. Future-Proof Architecture Required: - Code must be structured to easily add more recipes later - Recipe data in modular format (JSON array) - No hardcoding that prevents recipe expansion - Easy-to-add new recipe steps without code changes Technical Requirements: - Platform: iOS (14+) and Android (10+) compatibility - Bluetooth: Must use compatible libraries for both platforms - Recipe data stored in separate, editable file/structure - Each recipe step: `{temp: 85, timer: 90, instruction: "Preheat pan", ingredients: ["butter"]}` - Scalable design to add 10+ recipes in future updates Deliverables: - Complete Arduino .ino project - Mobile app source code (iOS + Android) - Modular recipe system (easy to add new recipes) - Wiring diagram & setup instructions - TestFlight build (iOS) + APK (Android) Must pass testing: - Test with one pancake recipe (all steps) - Hardware testing: ice water (around 0°C), boiling water (around 100°C) - 30-minute Bluetooth stability on both iOS and Android Milestones & Payment: 1. 25%: Basic temperature + Bluetooth working 2. 25%: App displays temp + C/F toggle + pancake recipe (both platforms) 3. 25%: Auto-timer feature complete with pancake steps 4. 25%: Modular system + cross-platform testing + delivery Timeline: 3-4 weeks (due to cross-platform requirement) Budget: Can't go higher than $350 Requirements: - Required: Arduino + Bluetooth experience - Required: Cross-platform mobile development - Required: Experience with iOS Bluetooth permissions/implementation - Portfolio of similar IoT cross-platform projects - Must demonstrate scalable code architecture I have all hardware ready. Looking for clean, expandable code that works on both iPhone and Android. To Apply: 1. Share similar cross-platform Arduino+Bluetooth projects 2. Your estimated timeline 3. Preferred cross-platform framework 4. Experience with iOS Bluetooth compatibility 5. How you'll structure code for easy recipe expansion