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dsPIC33FJ128GP Digital Signal Controller Family


The ability to measure heart rate and blood oxygen level is now being added to consumer products. These measurements can be taken using pulse oximeters that are intended for home medical use and by integrated wrist-worn fitness activity trackers.

A pulse oximeter is a device that uses a non-invasive method for measuring the oxygen saturation level of a person's blood, as well as their heart rate. LEDs in our Pulse Oximeter Demonstration transmit two wavelengths of light through a finger to a photo detector. From this, the Pulse Oximeter Demonstration can measure changing absorbance at each of the two wavelengths, process and then filter the data to determine the blood oxygen saturation level and heart rate.

Design Files Download

Pulse Oximeter Demo ‘C’ source code, application notes and schematics are available for this demo.

This demo is not for sale. Please download the design files for your evaluation and prototype development.

*Microchip medical reference designs and demos are intended for evaluation and development purposes only. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use.

Input and Filtered Data from Our Pulse Oximeter Demonstration


System Diagram


Demonstration Highlights


  • Measures heart rate
  • Measures percent blood oxygen saturation level
  • dsPIC33FJ128GP802 uses a 513th-order, digital-FIR, bandpass filter designed with our Digital Filter Design Tool
  • Eliminates the need for an expensive Analog Front End (AFE) part
  • Low overall BOM cost due to processing and filter integration
  • Integrated Pulse-Width Modulation (PWM) module drives the LCD display
  • MCP1640 boost regulator, MCP4728 DAC and the MCP6002 dual op amp used in the design for reliable and accurate power management and signal conditioning

Microchip's Pulse Oximeter Demonstration Board

Microchip’s pulse oximeter reference design demo board helps designers develop a low-cost, low power handheld or wearable pulse oximeter with user interface which is capable of measuring both heart rate and blood oxygen level. It can be used to start development of a hospital or clinical pulse oximeter design, but it can also be used as a starting point for the development of a wearable activity tracker design that can measure heart rate and blood oxygen level. 

http://www.microchip.com/medical