These are independent reviews of the products mentioned, but TIME receives a commission when purchases are made through affiliate links at no additional cost to the purchaser.

Battery capacity anxiety may soon be a relic of the past, at least for small electronics. Chinese consumer electronics manufacturer Oppo has designed a lightweight tracking device that can transmit information like location and temperature, while collecting what little power it needs from ambient energy sources like radio waves, light, and heat, so it never runs out of power. The technology, which Oppo aims to commercialize within the next year, could someday be applied to other small devices.

More Must-Reads from TIME

Contact us at letters@time.com.

Hydration Made Fun
A Modern Flip Phone
A Saliva Pregnancy Test
More Than a Fast Car
A Breakthrough Bassinet
EDIT POST