Design and Development of Drybath Incubator for Chemical Test Tubes with Fuzzy Logic Controller

Abstract

Clinical Pathology Laboratories require equipment for incubating samples and chemical reagents at temperatures between 25°C and 45°C. Commonly used waterbaths have limitations including contamination risk, temperature inaccuracy, and lack of incubation time display. Additionally, non-standard incubation practices such as holding test tubes in hands are often performed, reducing test result precision. This study aimed to design and build a drybath incubator for chemical test tubes with a fuzzy logic-based temperature control system and integrated timer. The system employs a hollow aluminum block, cartridge heater, waterproof DS18B20 temperature sensor, Arduino Mega microcontroller, and a 3.5-inch TFT LCD touchscreen. The fuzzy logic controller regulates temperature from 25°C to 45°C. Testing included accuracy, stability, temperature distribution uniformity, and timer precision tests across 25 holes (20 holes Ø 1.25 cm and 5 holes Ø 1.5 cm). Results showed temperature accuracy of 99.99%–100.00%, temperature stability with fluctuations below ±0.4°C, uniform temperature distribution with 99.98%–100.00% accuracy, and timer accuracy of 99.994%. The system proved capable of replacing waterbaths as incubators for chemical reactions in clinical pathology laboratories.