3-Phase Motor Auto Switch Design

Project Title: Hardware & Firmware Design for 3-Phase Submersible Motor Auto Switch (Low-Cost MCU) Project Scope: Looking for an experienced Embedded Hardware & Firmware Engineer to design a low-cost, mass-manufacturable 3-Phase Auto Switch with Single Phasing Protection (SPP). Technical Specifications: Input: 415V AC, 3-Phase (50 Hz). Transformerless capacitive dropper power supply (12V for relay, 5V for MCU). Sensing: Phase sequence/unbalance and single-phase failure detection via optocoupler or resistor network. MCU: Ultra-low-cost 8-pin or 14-pin MCU (e.g., Padauk, Nuvoton N76E003, or Puya/STC). Output: 1x 12V Cube Relay (SPDT) to actuate motor starter + 3 status LEDs (Timer, SPP, OK). Firmware Logic: 30–45 sec power-on delay timer; trip relay within 2–3 sec if any single phase is missing. Form Factor: Compact single-layer or 2-layer PCB designed to fit standard small ABS enclosure. Mandatory Deliverables: Complete Schematic & PCB Layout files in KiCad / EasyEDA. Production-ready Gerber files. Detailed Bill of Materials (BOM) with manufacturer part numbers (MPN) and sourcing links. Well-commented Embedded C source code (.c, .h) and compiled .hex file. 100% IP rights and source code transfer to the client. Budget: (₹15000 – ₹18000)