A Pulse Oximeter is a non-invasive device for measuring the percentage of arterial blood (or hemoglobin) that is saturated with oxygen. This device can also measure heart rate. Pulse Oximeters are used in medical, sports training and home appliance applications. Knowing the percentage of hemoglobin that is saturated with oxygen is important to provide anesthesia, to determine the effectiveness of a patient's respiratory system, as well as help to diagnose various illnesses.
The principle of operation of a Pulse Oximeter is based on measuring the absorption of red and infrared light that passes through a patient's finger or ear lobe by utilizing light sensors. Hemoglobin that transports oxygen (oxy-hemoglobin) absorbs infrared wavelength (800-940 nm) of light and hemoglobin that does not transport oxygen (deoxy-hemoglobin), absorbs visible RED wavelength (600-700 nm) of light. Backgrounds such as fluid, tissue and bone are factored out of the measurement by monitoring the steady state of absorption from bone, tissue, venous blood and arterial blood. LEDs are used as the light source and are sequentially pulsed at a fast rate. During a heartbeat, blood volume increases and this AC component of the photodetector's current is used to calculate the absorption of oxy- and deoxy-hemoglobin.
PSoC enables a scalable one chip pulse oximeter solution that flexibly integrates all the basic and advance requirements of a pulse oximeter. PSoC can also enable more advanced features for innovating Pulse Oximeters including USB, Graphics Display, and CapSense buttons. Finally, PSoC can also integrate numerous vital sign functions such as Blood Pressure Monitor, IR Thermometer, and Pulse Oximeter into a single chip solution.