Batteries not included: How small-scale energy harvesting will power the future

battery technology energy icon indicatorsThe venerable crystal radio has been around since the early 1900s, but for one very unique reason, people still build and use them today. It isn’t particularly loud, it won’t grab faraway stations, and its esthetics certainly won’t impress your hoity-toity buddies. However, this old school marvel offers a single perk no other radio can: It functions without traditional power sources. That’s right – no cord, no batteries, no hamster wheels.

How is this possible? Because crystal radios grab all the power they need from the radio waves themselves.

Pretty cool, right?

Radio waves, you see, are energy. It works like this: Radio stations convert audio into radio waves that then travel, at the speed of light no less, omnidirectionally from the transmitter. These waves are, in essence, electromagnetic fields – forms of electrical energy not too dissimilar from the power that flows to your AC outlets, only they’re sprayed in all directions. The fractional amount that actually reaches your home is not very potent at all.

Bereft of other power sources, the crystal radio needs to “harvest” as much of the approaching electromagnetic field as possible. It does so with a rather considerable antenna (usually a long stretch of copper wire), a “coil” that’s tuned to the frequency (number of waves per second) of the desired station, a “detector” to extract the audio signal, and an earphone to convert the audio signal back into sound waves.

Though the crystal radio itself fell out of vogue some time ago, the “energy harvesting” part of the equation – whereby power is gobbled, both literally and figuratively, out of thin air – is now in the midst of a notable renaissance. From harnessing the frenetic energy of a dance club to utilizing the heat given off by the human body, engineers are looking to the world around us for untapped sources of energy. And getting results. Here’s why power outlets and batteries are no longer good enough, and what scientists are doing about it.

It’s all about our hunger for power. We begin our days operating various devices around our homes – alarm clocks, toasters, coffee pots. We then hop in our car, which itself has an unquenchable thirst for even more energy. Or maybe we grab the bus, toying with our notebook or tablet or smartphone or music player or handheld gaming system along the way. Ultimately, our entire day plays out as it began – dependent on various forms of electricity to do what we need to do. 

Mobile

Want more power, but faster? This new charging tech claims it can deliver

Chunky power bricks and slow charging could be a thing of the past with GaNFast technology from Navitas Semiconductors. By using an alternative to silicon, GaNFast reduces power consumption and boosts output.
Outdoors

The best battery packs and power stations for use in the outdoors

If you want to keep your smartphones, tablets, and other devices charged while camping int he backcountry these battery packs and portable power stations are rugged enough to survive while providing plenty of power too.
Emerging Tech

Meet Wiliot, a battery-less Bluetooth chip that pulls power from thin air

A tiny chip from a semiconductor company called Wiliot could harvest energy out of thin air, the company claims. No battery needed. The paper-thin device pulls power from ambient radio frequencies like Wi-Fi, Bluetooth, and cell signals.
Home Theater

Banish the bunny ears (and monthly bills) with these excellent HD antennas

When transitioning away from cable and satellite, finding the best HDTV antenna for your area can be touch. To help, we've compiled our picks of the best indoor HDTV antennas you can buy.
Gaming

Can gamers build a society? We’ll find out in Amazon’s ‘New World’

Amazon is building a massively multiplayer game with an entirely unique world and setting. We interviewed three of the game developer’s about why Amazon is taking a risk on ‘New World’ and how the company’s cloud tech makes it…
Emerging Tech

Today, hacks are annoying. In future smart cities, they could kill

Corporate security breaches are becoming so common that people now accept them as part of a digital future. But for smart cities, system hacks could prove far dangerous for citizens.
Gaming

Ride through the sky and get fit on the fly with the NordicTrack VR Bike

During CES 2019, we tried the NordicTrack Virtual Reality Bike. Combining fitness and gaming, the bike is one of the most interesting approaches to VR traversal we’ve seen. 
Digital Trends Live

Digital Trends Live – CES 2019 – Day 2

On today's episode: While we are for sure going to run down all the hottest and most innovative tech announcements of CES 2019, we're also hosting some amazing guests and panels. From the latest VTOL taxi from Bell Helicopters and the…
Mobile

The best CES 2019 health gadgets combat stress, pain, and more

We can all use some help with our health and CES 2019 was packed with intriguing devices designed to combat pain and stress, help you monitor blood pressure, reduce tinnitus, and care for the sick or elderly.
Gaming

These shoes let me stroll through ‘Skyrim,’ and I desperately want to go back

After being funded in just two hours on Kickstarter back in October 2018, Cybershoes has earned itself a place among the coolest VR walking and running tech. At CES 2019, we got to try them out and they live up to the hype.
Smart Home

Treat your furry friend with the best pet tech at CES 2019

We all want the best for our feline companions and furry best friends, so we're seeing more and more innovative gadgets designed for pets. CES 2019 was a veritable treasure trove of pet tech and these devices are our picks.
Computing

It took three years, but OLED laptops are having another moment at CES

To our surprise, OLED laptops made a strong showing at CES 2019. With options in the works from most of the major PC manufacturers, it seems OLED is making its comeback.
Smart Home

Booth babes, banned sex toys, and other mishaps at CES 2019

From female sex toys bans, to fake Tesla/robot collision stories, there was some weird stuff going on at CES 2019 this year. Here are some of the biggest mishaps and flubs at the world's biggest tech show.
Computing

Nose cam no more. How Dell avoided a notch and fixed the XPS 13’s biggest flaw

The new Dell XPS 13 moves the webcam from the below the screen to the top, finally vanquishing the one obstacle facing thin, sleek laptop displays. We have the exclusive story on how it was done.
1 of 7