Developer for 4G and LoRa-based Device

We are seeking a skilled developer or team to design and develop a dynamic 4G and LoRa-based device with integrated MQTT communication and call functionality. The device should be compact, reliable, and capable of seamless data transmission via MQTT protocol while supporting voice call capabilities. The project includes hardware and firmware development, ensuring scalability and dynamic performance. Project Requirements: 1. Hardware Specifications: A 4G module for high-speed cellular connectivity. LoRa module for long-range communication. Microcontroller unit (MCU) to manage operations efficiently. Support for SIM card insertion for cellular functionality. Integrated microphone and speaker or support for external peripherals for voice calls. Adequate power management system for energy-efficient operation. Robust enclosure design suitable for field deployment (optional but preferred). 2. Firmware Features: MQTT protocol implementation for bidirectional data communication. Support for secure MQTT connections (e.g., TLS/SSL). Dynamic configuration options for MQTT broker settings. Call handling features, including initiation, reception, and termination of voice calls. Over-the-air (OTA) firmware updates capability. System diagnostics and logging capabilities. Fail-safe mechanisms and recovery options for robust operation. 3. Software Development: Development of a user-friendly configuration interface (e.g., web or mobile app) to manage device settings dynamically. Dashboard to monitor data and device health (optional but preferred). 4. Testing and Validation: Comprehensive testing to ensure device reliability and performance under various conditions. Validation of MQTT communication and call functionality. Compliance with relevant regulatory standards for communication devices. 5. Deliverables: Fully functional hardware prototype. Source code for firmware and software applications. Detailed documentation, including circuit diagrams, firmware logic, and user manuals. Post-project support for bug fixes and minor enhancements. Skills Required: Proficiency in hardware design and embedded systems development. Expertise in 4G and LoRa technologies. Experience with MQTT protocol and secure communication implementation. Familiarity with voice call integration in embedded systems. Strong knowledge of power management and low-power design principles. Ability to provide end-to-end development, including prototyping and testing.