This study aims to develop and evaluate a cost-effective Internet of Things (IoT)-based heart rate monitoring armband that addresses the limitations of existing devices lacking wireless connectivity for real-time data transmission in dynamic and remote monitoring contexts. A mixed-methods approach was employed to assess device functionality, usability, and effectiveness. The armband utilized ESP32 NodeMCU microcontroller and Blynk mobile application platform for wireless transmission. Purposive sampling recruited volleyball players (n = 30) from Aklan Catholic College, Philippines. Following cardiologist validation, data were collected through structured surveys and semi-structured interviews across multiple activity levels (rest, walking, running). Quantitative analysis revealed excellent functionality (M = 3.41), usability (M = 3.43), and effectiveness (M = 3.43) on a 4-point Likert scale. The armband demonstrated reliable real-time heart rate detection across varying intensities: rest (M = 3.29), walking (M = 3.27), and running (M = 3.29). Qualitative feedback identified enhancement opportunities including strap comfort, battery longevity, sensor precision, and water resistance. The study was limited to a single institution and specific user demographic. The IoT-enabled armband represents a reliable, user-friendly, and economically viable solution for cardiovascular monitoring, with significant potential for remote patient monitoring systems and broader healthcare applications.