_____________________________________________________________________________________________________ *Corresponding author: Email: benadegoke@fedpolel.edu.ng, adegokebo35@gmail.com; Journal of Engineering Research and Reports 21(1): 38-48, 2021; Article no.JERR.73117 ISSN: 2582-2926 Design and Construction of a Microcontroller-Based Driver Alcohol Detection System (MDADS) O. Adegoke Benjamin 1* and F. Oladoye Stephen 2 1 Department of Computer Engineering, School of Engineering, Federal Polytechnic, Ile-Oluji, Nigeria. 2 Department of Computer Science, Osun State Polytechnic, Iree, Osun State Nigeria. Authors’ contributions This work was carried out in collaboration between both authors. Both authors read and approved the final manuscript. Article Information DOI: 10.9734/JERR/2021/v21i117437 Editor(s): (1) Prof. Hamdy Mohy El-Din Afefy, Pharos University, Egypt. Reviewers: (1) Mirkhosil Agzamov, Tashkent institute of textile and light industry, Uzbekistan. (2) Mohamad Hussein Farhat, Australian College of Kuwait, Kuwait. Complete Peer review History: https://www.sdiarticle4.com/review-history/73117 Received 20 June 2021 Accepted 10 September 2021 Published 06 October 2021 ABSTRACT Aims: Vehicle accidents on most highways had caused a lot of losses. Many sustained injuries that marred them and left families helpless. Nigeria highways are not exempted. Drunk-driving increases tendency, severity and causality of crashes. Effects of auto crash damage to lives and properties necessitated the development of the Microcontroller-based Driver Alcohol Detection System (MDADS). Study Design: The system employed ATMega328p microcontroller (CU) which coordinated operations of 7 units that made the MDADS. The units are: Sensor Unit (SU), Switch (S), Power Unit (PU); LCD Indicating Unit (LIU), Alarm Unit (AU), DC motor (Ignition) Unit (IU) and Liquid Crystal Display Unit (LCDU). Place and Duration of Study: The study was conducted for 7 months in the Department of Computer Engineering, Federal Polytechnic Ile-Oluji (FEDPOLEL), Nigeria. It was conducted between October 2020 and July 2021. Methodology: Once the MDADS is ON, it assesses presence of alcohol in the endogenous alcohol molecules from the driver with the help of the SU. The SU sends signal to CU to control and sends signal to trigger the IU, AU and the LCDU of the MDADS, if the Blood Alcohol Content (BAC) exceeds the stipulated threshold 0.29ml/l. 60s tolerance was given to driver to switch OFF the ignition. If driver refuses to comply by switching OFF the ignition, the CU sends a “SWITCH Original Research Article