It’s a lot easier to change the batteries in a flashlight than to switch out the batteries in, say, a biomedical monitor. But eventually, such batteries might never have to be changed thanks to a new breed of heat-harvesting electronics developed by researchers at MIT.

Professor Anantha Chandrakasan and alumnus Yogesh Ramadass have developed so-called “energy-scavenging systems” that can gather power from temperature differences between an object (like the body) and the air. The systems can’t produce much power yet — just 100 microwatts from a temperature difference of one to two degrees. But that could still be enough to power biomedical devices (i.e. heart rate and blood sugar monitors) or other low-power electronics located in hard-to-reach spots, such as air quality monitors in heating and ventilation ducts or exhaust gas monitors in the flues of industrial plants.

There’s still plenty of work to be done before heat-powered electronics come into use. Anyone wearing a heat-powered blood sugar monitor on their arm, for example, also has to wear a metal heat sink. But once the MIT researchers refine their system, the devices could revolutionize the way we think about powering low-energy electrical devices.