We're approaching the point where someone will put together every form of energy harvest, solar, kinetic, temperature, air pressure (from wind, etc) and just store it in a super-capacitor for whatever you are wearing/holding, watch, phone etc.
Garmin already has solar on many watches to extend battery and the Kinefox is already doing kinetic on animal tracking
https://journals.plos.org/plosone/article/figure/image?downl...
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