Construction and Testing of an Arduino-Based Digital Thermometer for Clinical Use in Primary Health Centres in Ogun State

Background: Accurate temperature measurement is a fundamental clinical diagnostic parameter. Many primary health centres in South West Nigeria still depend on fragile mercury thermometers, which carry safety and accuracy concerns. Aim: This project constructed and tested an Arduino-based digital thermometer suitable for clinical deployment in primary health centres in Ogun State. Methods: A DS18B20 waterproof digital temperature sensor interfaced with an Arduino Uno microcontroller served as the measurement core. Readings were displayed on a 16x2 LCD screen. Calibration was performed against a certified mercury reference thermometer across a range of 35 to 42 degrees Celsius. Clinical testing involved 80 temperature measurements on consenting adult volunteers. Results: The digital thermometer showed a mean absolute error of 0.08 degrees Celsius relative to the reference standard. Response time was under five seconds. The device operated reliably on a 9V battery for up to 14 hours. Cost of construction was NGN 6,800. Conclusion: The Arduino-based digital thermometer is accurate, durable, and affordable for primary care settings. Its adoption in rural primary health centres can improve diagnostic reliability while eliminating mercury hazard risks. The study recommends integration of Bluetooth data logging capability in future iterations. Keywords: digital thermometer, Arduino, DS18B20, primary health care, Ogun State.