Design and Development of a Low-Cost Automated Coloured-Paint Mixing System for Small and Medium-sized Enterprises

Manual and semi-automated paint mixing in small and medium enterprises (SMEs) across sub-Saharan Africa, particularly Nigeria, generates significant colour inconsistency, material waste of 10–15%, prolonged cycle times, and low productivity. This paper presents the design, development, and evaluation of a low-cost automated colour mixing system tailored for resource-constrained environments. The prototype integrates a gravity-assisted mild steel frame fabricated from recycled industrial drums, three upper pigment storage tanks (Tanks A, B, and C), a central mixing tank (Tank D), 12V DC motors with peristaltic-style pumps, an Arduino Uno-based control system, and a custom real-time human-machine interface (HMI) named Messager Genius Auto Paint Software. A hybrid RGB/RYB colour model with empirical calibration matrices was employed, supporting both preset and custom colour selection. Testing across ten colour formulations achieved an average colour difference of ΔE = 1.65 (90% success rate at ΔE < 2.0), reduced material waste to 3.7%, and completed a 5-liter batch in approximately 9.4 minutes (58% improvement over manual methods). This work demonstrates the technical and economic feasibility of frugal mechatronics for pigment-based paint production in developing economies.