IoT-Enabled Hybrid Wiper and Micro-Mist Spray System for Autonomous Solar Panel Cleaning: A Rain-Aware ESP32 Prototype to Recover Soiling Losses While Reducing Water Use

This research paper presents the design and prototype of an IoT-enabled hybrid wiper and micro-mist spray system for autonomous solar panel cleaning. The proposed system uses an ESP32 microcontroller and a rain sensor to monitor wet and dry conditions and control the cleaning cycle automatically. The system combines a low-flow micro-mist spray with a silicone wiper driven by a DC motor through an L298N motor driver. A threaded-rod mechanism guides the wiper across the solar panel surface. The spray is designed to soften dust and dirt before wiping, while rain-aware control helps avoid unnecessary water use during rainfall. The prototype uses an aluminium rail, 3D-printed components, a rain sensor, a motor driver, and a micro-diaphragm water pump. The proposed design aims to provide an affordable and practical solar panel cleaning solution for small-scale and residential solar installations. The design targets are to recover up to 26% of soiling-related efficiency losses and reduce water consumption by approximately 60% compared with conventional washing. These figures are estimates and have not yet been validated through field measurements. Further work will focus on complete sensor and IoT integration, field testing, energy-output measurements, water-consumption analysis, and cost evaluation. This work supports the development of affordable renewable-energy maintenance technologies and aligns with Sustainable Development Goals 7 (Affordable and Clean Energy), 9 (Industry, Innovation and Infrastructure), 12 (Responsible Consumption and Production), and 13 (Climate Action).