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When you flick a normal light switch, it completes a circuit that ensures electricity is running to the lighting fixture or the outlet that your lamp is plugged into. This all happens through wires: The lights you want to connect to the switch are bound by long strands of copper in the walls. It doesn't have to be that way, though. And there's an alternative that doesn't require a battery that could render your switch useless.
On the show floor of CES 2026, I saw switches, locks and more connected home gadgets that were able to send the signals needed to make things happen in the home without needing a battery. Gemns showed one approach that used magnets to generate quick pulses of power with enough juice to send strong smart home signals -- and they even come with a satisfying click.
Energy harvesting isn't the only way to power things wirelessly: A demonstration by the startup Willo of a truly wireless charging solution that could power anything within a range of the device was sufficiently mind-blowing for my colleague Katie Collins that the CNET Group recognized it with our Best of CES Award for Energy Tech. New smart locks from the company Lockin use a technology the company calls AuraCharge to power the devices wirelessly through a beam of light, with a range of 4 meters as long as there's a clear line of sight. Other devices throughout the show use solar technology to capture enough ambient light to keep a battery charged.
Read more: The Home Tech Gadgets That Stole the Show at CES 2026
"Everyone's talked about the [Internet of Things] and how it's going to expand into billions and billions of sensors, and it hasn't quite happened yet," Larry Richenstein, the founder and CEO of Gemns, told me. "And the reason is batteries. It's very expensive to put these devices up in places that they're remote and then have to change the batteries when they run out every year or so."
The Gemns G200 can generate a burst of electricity with just a small bit of motion, like a snap. This little gadget is about 1 inch in diameter -- roughly the size of a quarter.
Jon Reed/CNETThe goal of all of this is something that can run without having to replace batteries or run wires. Sure, there are energy savings if you don't have to use grid power, but smart home devices tend to use small amounts of energy to begin with. Smart locks can run off of a handful of alkaline batteries. Security system sensors can use some basic replaceable batteries.
It's more a matter of seamlessness and ease of use. I've found few home tasks more annoying than trying to figure out what sensor or smoke detector is low on battery -- and then making sure you have the right battery for the job. It's annoying when it's a AA or AAA, more annoying when it's a 9-volt and downright infuriating when it's some bespoke battery you can't buy at the corner store.
Watch this: Lockin Powers Up Your Smart Lock With An Invisible Beam
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At its core, Gemns relies on forcing a magnet to spin quickly when a physical action occurs, like turning a doorknob or flipping a switch. That action generates a small amount of power that can be captured in capacitors and discharged for a simple, controlled action. Think scanning an ID for a lock or reporting that a door was open or closed.
The company showed off a variety of products that can generate power and send different signals. One light switch included a dimmer, allowing you to set the power intensity of a light before you hit the switch. It could then turn on a smart light wherever it was in range of the switch's signal -- no need to keep the lamp in one particular corner of the room.
Devices powered by Gemns' technology won't always be on, so something that requires a constant connection might also require a battery or might not be a good fit. Still, the company expects to start licensing its power tech soon, allowing you to soon have smart home devices that won't require you to change a battery.
