This reference design enables a wearable: optimized saturation of peripheral capillary oxygen (SpO2) and multi-sensor: multi-wavelength optical heart rate monitor (HRM). It uses AFE4420 device: which is a single-chip: bio-sensing front end for photoplethysmography (PPG) measurements. It supports up to four switching light-emitting diodes (LEDs) and up to four photodiodes to enable signal acquisition of up to 16 Phases. The CC2640R2F device (supporting Bluetooth® low energy 4.2 and 5) transfers the measured data to a remote location. This patient-monitoring design uses a single CR3032 battery with a 30-day life cycle. Raw data is available to calculate heart rate: SpO2: and other related parameters. 2 onboard light-emitting diodes (LEDs) identify low-battery detection and a Bluetooth connection.