The latest generation of sweat based batteries are reaching impressive power levels. The Electronic skin based Biofuel Cell (E-BFC) produced by the University of California San Diego are now producing a wearable patch that can produce over 1mW. That is more than enough to power a Bluetooth Low Energy (BLE) radio which was using only .4mW during testing.
The stretchy sticker like patch is applied to the skin and powers itself from lactic acid found in our sweat. Monitoring lactic acid would help provide more information about muscle fatigue. Future versions of a sweat patch could also be used to monitor glucose and hydration levels while providing enough power to transmit data to a smart phone app.
