Warning: file_get_contents(https://ojs.journalbusiness.my/ojs.php): failed to open stream: HTTP request failed! HTTP/1.1 404 Not Found in /var/www/ojs.unud.ac.id_backup/lib/pkp/includes/functions.inc.php on line 4 Lukito, Pandu, Supardi, I Wayan, AND Ratini, Ni Nyoman. " Design of a Heartbeat Detector Using a Photopletysmograph Method Based on an ATMega328 Microcontroller" BULETIN FISIKA [Online], Volume 24 Number 2 (5 August 2023)