App note on Renesas’ pulse oximeter basics and its applications. Link here (PDF)
The Renesas OB1203 pulse oximeter module optically detects heart rate and blood oxygen saturation (SpO2). Respiratory rate and other health information that can be inferred from the optical pulse waveform (PPG) signal. The OB1203 also features a proximity sensor and ambient light color sensor. A unique feature is OB1203’s 690nm far red LED which allows for use of IR-transmissive inks to hide the sensor under a cover glass, as is typical for proximity sensors.
The OB1203 module is a 4.2×2×1.2 mm OSIP (optical system in package) allowing for very compact industrial designs using the reflective PPG sensing mode.