43C Corporation

Develop and optimize ultra-low power firmware for a handheld ESP32-S3 IoT device with secure OTA updates and cloud integration. | 5+ years embedded systems experience with ESP32, proficiency in C/C++, power optimization, FreeRTOS, and secure IoT connectivity. | We are developing a specialized handheld IoT device based on the Waveshare ESP32-S3 microcomputer architecture. The device is critical-mission hardware that requires high availability and must operate for extended periods on battery power. We are looking for an expert who can bridge the gap between hardware constraints and intelligent software design to create a device that is both robust and energy-efficient. Key Responsibilities1. Firmware Development & Architecture • Develop robust, production-grade firmware for the Waveshare ESP32-S3 (Dual-core Xtensa® LX7) using ESP-IDF (preferred) or Arduino framework. • Architect a system state machine that prioritizes high availability while adhering to strict power budgets. • Implement secure Over-the-Air (OTA) update capabilities to ensure the device can be maintained remotely without user intervention. 2. Extreme Low-Power Optimization • Primary Challenge: Design the system for ultra-low power consumption to maximize battery life in a handheld form factor. • Implement and fine-tune Deep Sleep and Light Sleep modes, utilizing the ESP32's ULP (Ultra Low Power) coprocessor for sensor monitoring while the main cores are sleeping. • Profile power usage at a micro-amp level and optimize code execution to minimize "radio-on" time. 3. Power Management & Hardware Integration • Design the battery subsystem: Select appropriate battery chemistry (LiPo/Li-ion) and integrate a Battery Management System (BMS) or fuel gauge IC to accurately monitor charge levels. • Handle safe charging logic and voltage regulation circuits suitable for a handheld device. • Interface with peripherals (screens, buttons, sensors) ensuring they do not drain power significantly when idle. 4. Connectivity & Cloud Integration • Develop a reliable data transmission strategy. While the device supports Wi-Fi, you must determine if Wi-Fi, BLE, or a store-and-forward approach is best for the energy budget. • Implement secure IoT protocols (MQTT, HTTPS, or CoAP) to transfer data to the cloud (AWS IoT, Azure, or Google Cloud). • Handle "edge cases" in connectivity (e.g., buffering data when offline and syncing efficiently when a connection is re-established). Required Qualifications • Experience: 5+ years in embedded systems development. • Hardware: Deep familiarity with the ESP32 ecosystem, specifically the S3 variant and Waveshare development boards. • Language: Proficiency in C/C++ (Embedded). • Power: Proven track record of delivering battery-operated devices with multi-month/year battery life. You should be able to explain how you handled sleep currents and wake-up triggers in previous projects. • Connectivity: Experience maximizing Wi-Fi throughput while minimizing on-time, or implementing alternative transport layers. • RTOS: Strong understanding of FreeRTOS (tasks, queues, semaphores). Preferred / Bonus Skills • Experience with hardware design (PCB layout) in KiCad or Altium (in case we need to move off the dev kit to a custom board). • Knowledge of enclosure design for handheld devices (3D printing / CAD). • Experience with AWS IoT Core or similar cloud backends. If you have a brief summary of the most power-constrained device you have built to date would be helpful to understand the battery life achieved and the microcontroller userd.

Lead full-stack mobile app development across iOS and Android, manage cloud backend services, integrate web APIs, optimize performance, and handle deployment pipelines. | 3+ years professional mobile development with cross-platform frameworks, published app portfolio, cloud backend expertise (Firebase), native development knowledge, and testing experience. | Role Summary We are seeking a highly skilled and motivated Mobile Platform & Cloud Integration Developer to lead the development of our flagship application across all major mobile platforms (iOS and Android). This role is critical for delivering a fast, reliable, and deeply integrated experience, requiring expertise in both front-end mobile development and scalable cloud-based data storage and service integration. You will be responsible for the full development lifecycle, from technical design and implementation to deployment and maintenance. Key Responsibilities • Full-Stack Mobile Development: Architect, build, and maintain high-performance mobile applications for both iOS and Android from a single codebase (e.g., Flutter or React Native). • Cloud Backend Management: Design, implement, and manage scalable data structures and user authentication using Firebase (e.g., Firestore, Cloud Functions, and Firebase Authentication) or comparable NoSQL/cloud services. • Web/API Integration: Develop and maintain RESTful APIs and GraphQL connections to integrate the mobile application with existing web services and third-party platforms. • Performance & Optimization: Identify and resolve performance and scalability issues, including API latency, database query optimization, and UI rendering efficiency across diverse mobile hardware. • DevOps/Deployment: Manage the CI/CD pipeline for both Apple App Store and Google Play Store releases, including signing, testing, and deployment processes. • Collaboration: Work closely with UX/UI designers and product managers to translate concepts into high-quality, pixel-perfect user interfaces and intuitive features. Required Qualifications (Must-Haves) • Experience: 3+ years of professional experience in mobile application development. • Portfolio/Samples: Must provide links to existing mobile applications developed and published to the Apple App Store or Google Play Store, or links to a verifiable code portfolio (e.g., GitHub). • Cross-Platform Expertise: Expert proficiency in a cross-platform framework such as Flutter (preferred) or React Native, demonstrating mastery of Dart or JavaScript/TypeScript. • Cloud Backend Proficiency: Deep, demonstrable experience implementing and managing core services within a serverless architecture like Firebase (specifically Firestore for data persistence and Cloud Functions for backend logic). • Web Integration: Strong understanding of how to consume and process data from web APIs (REST/JSON) and secure the data flow between the client and the cloud. • Native Knowledge: Familiarity with underlying native development environments (Swift/Kotlin/Java) to handle platform-specific features, debugging, and module integration. • Testing & Quality: Experience with unit testing, widget testing, and end-to-end testing frameworks for mobile applications. • Tools: Proficient in using Git and managing complex branch workflows. Desired Skills (Nice-to-Haves) • Experience with other public cloud platforms (AWS Lambda, Google Cloud Platform, or Azure Functions). • Prior experience contributing to or maintaining existing native codebases (Swift/Kotlin/Java). • Familiarity with advanced state management techniques (e.g., Bloc, Provider, Redux) and architectural patterns (MVVM, Clean Architecture). • Experience in optimizing bundle size and app distribution. • This is a critical role for our team, ensuring our users receive the best possible experience across every touchpoint, from their mobile screen to our cloud backend.