Automotive monitoring systems increasingly depend on distributed sensors for acquiring speed and environmental information; however, traditional point-to-point sensor architectures lead to excessive wiring complexity, limited scalability, and reduced system flexibility. This work presents the design and experimental validation of a low-cost smart sensor node architecture that demonstrates bus-oriented automotive monitoring concepts using a minimal embedded hardware platform. The proposed system integrates a slot-type incremental optical encoder for speed measurement and a temperature–humidity sensor for environmental monitoring, with all signal processing performed locally on an embedded microcontroller. An interrupt-driven acquisition mechanism is employed to ensure accurate real-time pulse detection, while structured data transmission is used to emulate scalable bus-based operation. Experimental validation was conducted using a laboratory prototype, where encoder pulse data were recorded under varying operating conditions and analysed over fixed time intervals. The results demonstrate reliable pulse acquisition, consistent sensor behaviour, and stable operation under steady-state conditions, confirming the robustness of the proposed approach. The observed pulse saturation behaviour further indicates mechanical and computational stability of the system. Although a full automotive communication network is not implemented, the proposed architecture effectively captures the functional characteristics of intelligent sensor nodes used in modern vehicles. The study confirms that scalable and intelligent automotive monitoring architectures can be realized using low-cost embedded platforms, providing a practical and reproducible solution for academic research, early-stage prototyping, and cost-sensitive automotive applications.