True wireless power transmission, without cords or charging mats, has been a white whale for the technology industry for decades. But a new startup born out of the California Institute of Technology claims it’s figured out how to pull it off in a way that is small, cheap, and efficient enough to be commercialized. Called Guru, the company has built a wireless charging system that transmits electricity using high-frequency radio waves, specifically the millimeter wave (mmWave) variety that underpins burgeoning 5G cell networks in the US.

Next week at CES, Guru is unveiling three prototype charging products it wants to develop in partnership with electronics manufacturers, but the company gave The Verge an early look at the technology and explained how it works. The three prototypes include a desk charging system that can wirelessly charge pretty much any gadget within a few feet, a room-scale version the size of a ceiling tile that has significantly more range, and a roving Roomba-like robot that’s designed to move around a large space and charge small, smart home-style gadgets like cameras and IoT sensors.

“The idea of sending power of distance is not new. Nikola Tesla had that same idea that power should be sent wirelessly,” says co-founder and CEO Florian Bohn, who previously founded a cellphone component company called Axiom Semiconductor and worked on a CalTech initiative to harness solar power and beam it to Earth using microwaves. “What makes us different is we’re using very advanced technology as well as our system design and mmWave technology that allows us to send power in a controlled and safe and effective manner.”

And Bohn’s point is an important one. Wireless power transmission, as a concept, is over a century old, and scientists have proven that it does indeed work, thanks to experiments over the last few decades that have made use of more sophisticated radio technology. For the tech industry, over-the-air wireless charging for consumer gadgets has been kicking around for some time, too.

A number of startups tried and failed to get the idea off the ground, most notably New York-based uBeam, a troubled startup that’s been trying to use ultrasonic waves for wireless power transmission and repeatedly missed its deadlines for delivering a working product. Apple also recently filed a patent for this exact technology, and a number of other startups have either come to CES in years past or are planning to come to this year’s show to prove they have a working version of the idea.

But why should we take Guru seriously? According to Bohn, the company has two advantages. One is that it’s using mmWave, which are extremely high-frequency radio waves that allow for high precision. That way, Guru’s charger can identify the device that needs charging and send a localized beam of radio waves that transmit electricity, in a way that’s vastly superior to lower-frequency waves.

Image: Guru

But the real innovation Guru claims it has pioneered is something the company calls Smart RF Lensing. It’s a patented technology Bohn’s co-founder Ali Hajimiri developed at CalTech alongside Princeton University’s Kaushik Sengupta that involves controlling the direction and number of beams that get transmitted.

Effectively, Smart RF Lensing allows Guru to send multiple beams of energy to even tiny receivers, which is what allows the transmission devices to be shrunk down enough to fit on your desk or be mounted to a wall. It also allows Guru’s system to charge devices as small as cellphones and even smaller IoT and smart home devices.

“The core tech behind all of these applications is fundamentally the same thing — just different scales, power levels, and ranges,” Bohn says. “One of our strengths as a company is our tech has this versatility of usage: lower-power short distances up to very large power over long distances. The differences being the size and the cost point of the end product.”

But does it actually work? I watched a live demonstration over video chat of Guru’s system in action, and it did work as advertised. A member of Guru’s team showed off the desk system, which looks like a rather large heating lamp of sorts, activate a lightbulb sitting a few feet away. When the employee put his hand in between the two objects, the lightbulb turned off. The same was true of the room-scale charger and the roving Roomba-like one, which wheeled itself up to a light switch and activated it automatically once it was close enough. Guru is stressing that the use case is not lighting but charging batteries instead. But the light switches offer meaningful evidence that the system is indeed functional.

Guru envisions a system where you can control when the charging beams are active and manually turn them off when they encounter any interference, either through an app or by physically moving the device so there’s something in between. For instance, by picking up your phone and putting it your pocket. Bohn stresses that the beams are perfectly safe to travel through human beings and can do so through physical surfaces in most cases, but Guru wants users to be able to control this element of the system themselves. “The radio waves themselves are inherently non-ionizing. It’s very targeted. If your device is powered and you’re sitting nearby, you have almost zero exposure,” Bohn says. “Like all radio devices, we’re going through the same process of regulatory approval.”

For now, you still need physical receivers for a device to become compatible with Guru’s charging system, as the technology isn’t built into any existing consumer electronic devices. That means for smartphones, you would need to place a small rectangular receiver on the back of the phone. Guru says it’s working on making even smaller receivers for smart home gadgets. Bohn also says the charging rates are right now slower than what you’d get with a modern, USB-C power brick and more in line with a slower Qi wireless charger. But those could improve over time, too.

Guru’s success will depend on more than just charging times and receiver size. How the company gets its technology to consumers will be a big factor. Bohn says Guru is in talks with consumer electronics manufacturers about partnerships, as well as partners in warehouse technology and retail about commercial use of its wireless power system. It is also in talks with companies about licensing its tech to be incorporated into new products down the line.

How its physical products take shape will dictate whether Guru’s bold vision for easy, efficient, cost-effective, and cordless wireless charging becomes a reality or whether it becomes yet another failed attempt at an age-old idea. Another factor is whether the system will actually end up working better than existing plug-in charging and Qi charging options, both of which work perfectly fine if you’re okay with keeping cords around and manually inserting them into your devices or keeping a charging mat nearby. Beating the status quo will be Guru’s most consequential hurdle, and it’s an open question whether any company, let alone a startup, can push consumers to change a behavior that’s ingrained into how we use technology today.

But Guru’s vision is a bit grander than just eliminating cords. Bohn and his co-founders are confident that, if done right, a proper system for wireless power transmission could shift not just how we think about keeping devices charged and powered on at all times, but also the types of devices we end up using and what those devices get used for. Guru is envisioning a world where you can keep all manner of battery-powered gadgets, big and small, all over your home or in every corner of an office, store, or warehouse without having to worry about where they draw power from or how long it lasts on a single charge. That’s because power will be flowing through the air at all times to keep everything topped up, just as Tesla theorized more than 120 years ago.

“Most of the volume of your device is in fact battery,” says Hajimiri. “The reason is that it has to last you a long time. But once the charging is ubiquitous, it could change everything.”