Prayetno E, Nadapdap T, Susanti AS, Miranda D. PLTD Engine Tank Oil Volume Monitoring System using HC-SR04 Ultrasonic Sensor Based on Internet of Things (IoT). IJEEPSE [Internet]. 2021Feb.28 [cited 2024Apr.20];4(1):134-8. Available from: https://ijeepse.ejournal.unri.ac.id/journal/index.php/ijeepse/article/view/69