A group of students from Santa Clara University have developed a partially 3D printed wristband prototype that uses body heat, ambient air and heat sinks to create a temperature difference across thermoelectric modules, which generates extremely low voltage electrical power required to run the device itself. The device consists of four subsystems: power generation, voltage boost, battery charging and wearability and the device was 3D Printed using Formalabs Form 2 3D printer.

Source: https://scholarcommons.scu.edu/cgi/viewcontent.cgi?article=1040&context=idp_senior