Heat-powered hat
Pranav Vaidhyanathan and Alex Yamada modeling their heat-powered WeLumen8 hat. (Photos by Adam Lau / Berkeley Engineering)Pranav Vaidhyanathan, an electrical engineering and computer sciences student, remembers summer blackouts in his hometown of Chennai, India. It wasn’t unusual for electricity to be out for as long as 20 hours. Mechanical engineering student Alex Yamada could commiserate. Growing up on Oahu, Hawaii, Yamada remembers how the island would frequently lose power — especially after a big storm — primarily because of aging infrastructure.
Both were taking INDENG 185, a lab where they were challenged to develop technology for a global startup. Thinking back to their experiences, they teamed up with economics major Justin Kim to develop WeLumen8, a baseball cap with built-in LED lights powered by human heat.
While there are tiny thermoelectric generators that are commercially available for wearables, these can’t generate enough voltage to power LEDs. So to make the LEDs on the cap shine brightly, the WeLumen8 team developed a novel supercapacitor that amplifies the small amount of voltage from these commercial generators to 3.3V. WeLumen8’s technology also efficiently converts the heat energy from the body, unlike other efforts to do so.