The computer, medical equipment, and facilities often required for traditional electrocardiogram (ECG) measurements and displays usually bear some shortcomings, such as bulkiness, inconvenience in carrying around, high cost, and so forth. Based on embedded system architecture, this paper proposes a new design for an ECG measurement instrument and investigates the feasibility of such new design. Our system design adopts a Nintendo palm-type Game Boy Advanced (GBA) color video player and incorporates self-made ECG measurement circuits to develop a portable color ECG measurement system. In the heart rate computation, this paper proposes a new method deriving from improving the Peak Quantification Method (PQM) introduced by Navakatikyan, et al. Our experimental results verify that the improved method, when applied to heart rate measurements, possesses extremely high degree of accuracy. This study provides a method in utilizing a low-cost, portable GBA play machine for medical applications to augment the development direction for the future medical instruments. This proposed system has been completed with ECG measurement capability up to date. We will keep expanding said system's functions to include the measurements of phonocardiograms (PCGs), electroencephalograms (EEGs), and so forth, in the future.