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Pulse Oximeter | Cypress Semiconductor

Block Diagram

PSoC programmable analog & digital resources integrate everything shown in light blue below. Click on the colored blocks to view or sample the recommended PSoC Components.


The flexibility of PSoC allows you to customize each colored block, or PSoC Component, to meet your design requirements through the easy-to-use PSoC Creator Software IDE.  These Components are available as pre-built, pre-characterized IP elements in PSoC Creator.

Design Considerations

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.

Application Notes



Software and Drivers

  • PSoC Creator

    PSoC Creator is a state-of-the-art software development IDE combined with a revolutionary graphical design editor to form a uniquely powerful hardware/software co-design environment.

  • PSoC Designer

    PSoC Designer is the revolutionary Integrated Design Environment (IDE) that you can use to customize PSoC to meet your specific application requirements. PSoC Designer software accelerates system bring-up and time-to-market.