Index05 / project · 2025
A portable pulse and blood-oxygen monitor I built from scratch, from the LED sensing circuit up through the microcontroller firmware and the LCD readout.
EmbeddedCircuit DesignSensors
Build
Red and infrared LEDs shine through a fingertip while a photosensor reads what makes it through. Oxygenated and deoxygenated blood absorb those two wavelengths differently, which is the whole trick behind pulse oximetry. A microcontroller samples the signal, computes pulse and oxygen saturation, and pushes live readings to an LCD.
Image Coming Soon
Takeaways
Circuit design and signal cleanup took longer than the code. Real sensors are noisy, fingers move, and ambient light sneaks in everywhere, so most of the effort went into getting a stable reading.