World’s First Non-Battery Cell Phone “Harvests” Ambient Radio Waves to Power Itself


by Russel Davis, Natural News:
A team of computer scientists and electrical engineers at the University of Washington have designed and unveiled the world’s first battery-free mobile phone that makes use of ambient radio waves or light to function. The phone was touted to “harvest” a few microwatts of power from the said sources to send and receive calls. The team even reported placing Skype calls using the battery-free phone, which demonstrated that it can be used to receive and transmit speech and communicate with a base station. The phone was made of commercial, off-the-shelf components.

“We’ve built what we believe is the first functioning cellphone that consumes almost zero power. To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed,” co-author Shyam Gollakota stated in a university release.

“You can’t say hello and wait for a minute for the phone to go to sleep and harvest enough power to keep transmitting. That’s been the biggest challenge — the amount of power you can actually gather from ambient radio or light is on the order of 1 or 10 microwatts. So real-time phone operations have been really hard to achieve without developing an entirely new approach to transmitting and receiving speech,” co-author Bryce Kellogg quoted in an article posted on the Science Daily website.

This is how the battery-free phone actually works

Regular mobile phones take up too much energy in transmitting data, which involves converting analog signals containing sound into digital data that a phone can readily understand. To eliminate the need for power-consuming transmission, the researchers specifically designed the phone to rely on ambient power sources.

The battery-free mobile phone makes use of vibrations in a phone’s microphone or speaker, which occur when an individual talks to another phone or listens to a call. An antenna linked to those components converts the vibrations into altered standard analog radio signals emitted by a cellular base station. The process basically encodes speech patterns in reflected radio signals in a manner that utilizes almost zero power.

In order to transmit speech, the phone makes use of vibrations from the device’s microphone to encode speech patterns in the reflected signals. On the other hand, the phone converts encoded radio signals into sound vibrations picked up by its speaker in order to receive speech. The researchers designed the prototype device to contain buttons indicating “transmitting” and “listening” modes.

The team then used off-the-shelf components to demonstrate that the phone can perform basic functions such as sending and receiving data via buttons. The experts also used Skype to demonstrate that the battery-free phone can receive incoming calls, dial out and place callers on hold. The experts designed a custom base station to transmit and receive the radio signals. The team looks at the possibility of incorporating the base station into standard cellular network infrastructure or Wi-Fi routers.

“The cellphone is the device we depend on most today. So if there were one device you’d want to be able to use without batteries, it is the cellphone. The proof of concept we’ve developed is exciting today, and we think it could impact everyday devices in the future,” said faculty lead Joshua Smith.

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  1. That is very interesting, and probably will be a bit useful someday.
    But since they’re powering it, with 1-10 MICRO WATTs (millionth’s of a watt) you can buy a 2 watt (2,000,000 micro watts) Solar panel for less than FIFTY CENTS and power up that phone really easy (as long as there is sunshine hitting the solar cell).

    I’m glad they demonstrated some really interesting “energy harvesting” and efficiency techniques, but where the wheels meet the road, a cheap $5 solar panel (10 watts) is quick, easy and powerful enough to charge up a phone in the sunshine. (when you consider that the plug-in chargers for the big smart phones, are exactly 2A (about 10 watts), then you could get a 20-30 watt solar panel (for about $15-20) and even charge up the phone when the sun’s not fully bright.

    Every prepper should have some solar panels, charge controller, R/V battery, and inverter for those days when no other power is available. When you start to educate yourself about such things as “true sine wave” inverters vs. those that are not, and input voltages vs how much a single or double battery can (and cannot) put out, wire sizes, etc, you’ll be on your way to getting the right equipment the first time around and not making a bunch of mistakes based upon your lack of knowledge.

    (Hint= for a HOUSE sized, system, NEVER rely on 12VDC systems.) 12vdc is good, ONLY for in the car. When it comes to boats, campers, etc, even a 24vdc battery fed system is too small, especially the instant you turn on that 1000w microwave or blow drier.
    1000w powered by a 12vdc battery, needs to suck out about 100 AMPS of 12v battery power, to convert it into 120vac. Even a 24vdc battery fed system, needs to suck about 50A of battery power for the same job. But a 48vdc fed system, only needs to use 25A of battery power to do the same job.

    And if you know anything about WIRE sizes (to carry those amps), you’d know that you need at least 10ga wire for 25A (but don’t forget the SURGE capacity, means your 10ga wire is not fat enough, you’d need 8ga or even 6ga wire for your 30A breaker protected circuit.)

    How fat would that wire have to be to carry 100A of 12vdc power? (and you’ll actually have to get wire that can handle a 200A surge!) Just look at the FAT wire going into your HOUSE breaker panel (if you’ve got 200A service, then you are looking at the correct size!) OUCH.

    Pure copper CABLE, fat enough to handle 200A, is not cheap. And the CODES require it to be properly rated, such as 90C degrees temperature (194F), (so it won’t melt on a hot day carrying the full load.)

    THAT’s why you always set up solar systems, with higher voltage battery banks, etc., to save on the wires, and to avoid stressing the batteries from having to try to push out TOO many amps at once.

    • One look at the battery cables under the hood of your car or truck or that runs to your car’s starter motor should tell a person all they need to know about low volt / high amp systems and their wiring requirements. 🙂

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