How the device interacts with other device or with the user

The device can be used standalone as a blood pressure monitor, and it can upload the data to a PC/smart-phone via USB/Bluetooth respectively.

Explanation of the material used in the device
ECG electrodes: all 3 are gold-plated or platinum-plated (both are bio-compatible)
Pulse sensor: force sensor encapsulated with silicon rubber, which is also a bio-compatible material.
Mechanical: It includes a bottom case, a mid-frame, and a top lens.
Electronic: PCB with active and passive components powered by a rechargeable battery
Display: back-light LCD