Heart | Rate Monitor
and fitness trackers, these sensors use green LED lights to illuminate the blood vessels in your wrist. By measuring the changes in light absorption as blood pulses through, the device calculates your heart rate.
Most modern monitors use one of two primary technologies to detect your pulse: heart rate monitor
Commonly found in smartwatches
For those interested in electronics, building a heart rate monitor is a popular beginner-to-intermediate project. Enthusiasts often use an Arduino paired with a pulse sensor to display live data on an LED screen or serial monitor. Some even utilize smartphone cameras and flashes as makeshift optical sensors to extract pulse data through Python processing. and fitness trackers, these sensors use green LED