Wearables such as smartwatches or fitness trackers are increasingly being used for health surveillance.

The measurements are often carried out by optical sensors based on the principle of photoplethysmography (PPG) - for example to measure the heart rate.

Here light is blasted on the skin, usually by an LED, and the sensor measures how much light is reflected back. The blood flow in the vessels changes with every heartbeat, which influences the amount of the thrown back. These changes are converted into electrical signals, which can then be used to determine the heart rate.

As part of this project, a system is developed that captures the heartbeat through measurements on the index finger or wrist and visualizes the heart rate on a display. For the assembly of the hardware, a prefabricated kit is provided, consisting of a developer board, sensor, finger clip, display and housing. In combination with a simple software application, a simple but still effective measuring system can be realized. Previous knowledge is not required.