Abstract This paper presents the design, modeling, and experimental validation of a pendulum-based wave energy converter (WEC) developed to support autonomous marine sensing applications. The device houses a horizontally mounted pendulum inside a sealed, modular buoy, where wave-induced oscillations are harnessed to power onboard sensors, including temperature and turbidity units. A 1:8.5 scale prototype was built and tested in the wave tank at Davidson Laboratory under regular wave conditions. The buoy’s construction features stainless steel and polycarbonate, designed for durability and ease of maintenance. Froude scaling was applied to relate model-scale results to full-scale performance expectations. The experimental work included direct measurements of pendulum angular speed, shaft torque, generator voltage output, and mooring line tension. Results showed a strong correlation between wave frequency and pendulum rotation, aligning well with a predicted nonlinear behavior. Free decay tests, frequency analyses and power performance metrics are included. The study demonstrates the feasibility of a compact, self-powered platform for long-term, low-maintenance oceanographic monitoring.