Design, Implementation and Functional Validation of Raspberry Pi 5–MATLAB Dual-Channel Telemetry System for Graywater Process-Flow Monitoring

Pump status is not enough. An operator needs both the instantaneous rate and accumulated volume on the intended process path, together with the quantity diverted through overflow. This paper reports on a dual-channel telemetry system built around Raspberry Pi 5 and a networked MATLAB R2025b supervisory interface. The prototype uses two HKD YF-B5 G1/2-inch brass Hall-effect flow meters, one on the main line and another on the overflow line. A custom power-conditioning assembly accepts 12 VDC and establishes 12 V, 5 V and 3.3 V rails for sensor excitation, processor and relay interfacing, and GPIO-compatible signaling. Before GPIO 26 and GPIO 16 receive the sensor pulses, the interface circuit conditions them. MATLAB detects rising edges, calculates the inter-pulse period, converts pulse frequency to channel flow, integrates accumulated volume and updates four animated trends with a live numerical table. Timed 10 L collections gave mean reference flow rates of 9.003 L/min on the main route and 14.657 L/min on the overflow route. Single-point volume checks produced errors of 3.53% at 5.000 L and 9.25% at 2.000 L. A coefficient error in the overflow accumulator was corrected, and a fresh 2.000 L run returned 2.185 L. Validation remains limited to gravity-fed operation.