Device Scavenges Body Heat, Allows Crowds to Gather Safely

If efforts to maintain public safety amidst the ongoing pandemic have taught us one thing, it’s that we need better approaches to screening large groups of people. What if we could do away with swab and spit tests to quickly and efficiently identify those with elevated temperatures, one of the biggest red flags of viral infections?

Mechanical engineers at Texas A&M University have devised an innovative new approach to answering this question. Senior investigator Choongho Yu led a team that has created an electronic, wearable fever-detecting device fueled by an unusual energy source: body heat.

“Thermal energy scavenging shows great potential since an output voltage can be obtained by a temperature difference supplied by the fever,” said Yufan Zhang, one of the inventors of the technology. “To visualize the temperature changes, an electrochromic fever detector has been fabricated and connected to the thermal energy harvester.”

The design of their device leverages the principles of thermo-hydro-electrochemical energy conversion. Thermoelectric circuitry that converts dissipated heat into electrical outputs has, until now, only managed to generate very weak voltages. However, the team’s groundbreaking next-gen device can produce “colossal” voltages of an unprecedented 87 millivolts per degree Celsius.

A peek under shows that these energy outputs are a result of specialized special carbon steel electrodes. These electrodes gradually corrode over time, harnessing the ‘wasted’ heat of the wearer and powering a diagnostic system that the team predicts could remain functional for as long as a decade.

Once commercialized, such technologies could help us gather safely in social settings. The diagnostic, conceivably worn as a bracelet, would signal the wearer's fever, avoiding the need to measure temperatures in large crowds individually.