Embedded Hardware Engineer for MQTT Board

We are looking for an experienced Embedded Hardware Engineer / PCB Designer to design and prototype a custom control board for an environmental monitoring and automation system. The board will control multiple devices such as fans, actuators, and dehumidifiers while communicating with our central MQTT-based monitoring platform. This is a hardware design project that includes PCB design, component selection, firmware recommendations, and prototype support. Project Requirements Device Control The board must support: * 4-8 fans * 2-4 actuators * 2-4 dehumidifiers Total relay capacity should be: * Minimum: 8 relays * Preferred: 16 relays Fan Speed Control The board must support two-speed fan operation. Preferred implementation: * High-speed relay output * Low-speed relay output * Off state when both relays are disabled The system should prevent simultaneous activation of both speed relays for the same fan. MQTT Integration The board must integrate with our MQTT-based monitoring platform. The engineer should recommend and implement the best communication method: * WiFi * Ethernet * Serial communication The board should: * Receive MQTT commands * Parse JSON payloads * Execute device control actions * Report status back to the server Status Monitoring & Feedback The board should provide: * Relay state reporting * Device status feedback * Error reporting * Real-time state updates Examples: * Fan Relay #1 Activated * Fan Running High Speed * Device Offline * Communication Error Deliverables * Complete PCB schematic * PCB layout files * Bill of Materials (BOM) * Gerber files ready for manufacturing * Firmware architecture recommendations * MQTT communication design * Prototype testing guidance * Documentation Preferred Qualifications * PCB design experience (Altium, KiCad, Eagle, etc.) * ESP32, STM32, Raspberry Pi Compute Module, or similar embedded platforms * MQTT protocol experience * IoT device development * Relay and motor control systems * Industrial automation or environmental control systems * Firmware development experience is a plus To Apply Please include: 1. Relevant PCB/embedded projects you have completed. 2. Experience with MQTT and IoT systems. 3. Recommended controller platform (ESP32, STM32, etc.) and why. 4. Estimated timeline for design and prototype-ready deliverables. 5. Hourly rate or fixed-price estimate. We are looking for a senior-level hardware engineer who can own the design from concept through prototype-ready manufacturing files.