SEMI-AUTOMATIC GROWBAG FILLING MACHINE

Abstract

Growbag cultivation has emerged as a significant component of protected agriculture, particularly for vegetable and seedling nurseries. However, manual growbag filling is a highly labour-intensive and ergonomically demanding operation that creates labour bottlenecks, causes inconsistent fill weights, and exposes workers to musculoskeletal injury risks. While fully automatic filling machines exist, their high commercial costs make them economically unfeasible for small- and medium-scale nurseries. To bridge this technology adoption gap, a study was undertaken to design, develop, and evaluate a sensor-based, semi-automatic growbag filling machine tailored to the operational needs of local nursery operators. The machine's structural components were engineered based on the physical characterization of a standard 1:1:1 volumetric potting mixture of soil, coir pith, and farmyard manure. This mixture exhibited a total porosity of 24.49%, and an angle of repose of 60°. The machine utilizes a volumetric cell metering mechanism consisting of four cylindrical mild steel cups driven at 90° intervals, working in tandem with a rotating turntable platform that features eight growbag holder positions spaced at 45° intervals. The control automation circuit integrates industrial-grade motion controllers with an optical feedback loop managed by an Arduino microcontroller. Power transmission to the turntable is driven by a high-torque NEMA 23 planetary geared stepper motor and an ES-D1008 servo drive, connected via a flexible jaw coupling to dampen mechanical vibrations. Position tracking and bag detection at the filling station are accomplished using a TCS3200 RGB colour sensor module. Upon validating bag presence, the microcontroller executes non-blocking timing logic to actuate the metering gate, discharging a precise volume of substrate before advancing the turntable to the next position. Performance evaluation of the fabricated machine demonstrated high functional reliability and operational efficiency under field conditions. The automated system achieved a stable throughput of 500 bags per hour, representing a significant improvement over manual rates while reducing operator fatigue. Volumetric filling consistency was high. Built using standard materials and off-the-shelf electronic components, the total cost of fabrication is about 45,000, presenting nursery entrepreneurs with an accessible and economically viable alternative to manual labour