This trial was performed to examine the influences of finger sensor on the optical biosignal acquired from photoplethysmography (PPG). Besides examining the sensor components, factors such as sensor position, motion artifact, contact force and bad contact were also investigated. All sessions resulted in direct effects on the wave shape, AC and DC levels of the PPG signal. We concluded that the impacts of components, position and motion artifact can occur during measurement and suggested some subroutines in system algorithms to prevent them in practice. The bad contact and contact force were also influential though may not occur in practice credited to the advancements in commercialized sensors currently available in the marketplace.