The EngineAI SA01 is a fully open-source bipedal robot platform with 12 degrees of freedom and self-developed straight-knee gait technology. Hip and knee joints deliver 160 N·m peak torque using full-stack proprietary integrated joint modules with dual absolute magnetic encoders for quick position recovery after power cycles. The complete hardware architecture, interfaces, and motion control algorithms are open-source, allowing users to access underlying control code, modify algorithm modules, and deploy self-developed control strategies for real-world validation. The aviation-grade aluminum alloy body balances impact resistance with lightweight design. A 15 Ah (0.819 kWh) battery supports extended continuous operation. Designed for research and education in bipedal locomotion development.