Your iPhone has a low battery again?
Engineers at the University of Washington may have created a battery-free cell phone that uses power from ambient radio signals–and which doesn’t require any conventional battery to make calls or perform any other basic cellphone functions–including SMS texting. Say goodbye, iPhone battery!
The researchers managed to pull this off by changing the mechanism of conventional cellular transmission. Usually, in normal cellular usage, analogy voice data is converted into a digital signal that can be sent across the cellular network. But this conversion and propagation requires a lot of energy, approximately 800 milliwatts. The battery-free phone was able to reduce energy requirements to 3.5 microwatts–an over 1000-times improvement.
How? Rather than wasting signal energy in the analog-digital conversion, the phone keeps the data in analog. Instead, the mic picks up the tiny and, using a backscatter technique, the analog signal is detected on the nearby base station.
Okay, so maybe don’t say goodbye to your iPhone quite yet. Right now, the phone needs to be near a base station for the technique to work. But this could change if the system can be made to use ordinary cellular systems. In the near future, it’s possible that basic phone operations–calling, texting, etc.–may survive, even if your iPhone’s battery runs out of juice. Again.