Wouldn’t it be wonderful if, while you’re waiting to catch a plane at the airport, your smartphone could be charging with power through the air? That way, you don’t have to go sit on the floor in the corner next to a power outlet. Well, sorry to disappoint, but that’s not going to happen for the foreseeable future. There are a couple of obstacles that engineers aren’t even close to solving: consumer safety and power efficiency, which diminishes with distance.
However, a few companies are starting to innovate power-through-the-air technology to power small IoT sensors for use cases in industrial settings where there aren’t a lot of humans walking through the power field.
And this power-through-the-air technology could save the world a lot of tiny, environmentally unfriendly batteries, as well.
One company working in this space is Ossia, whose Cota technology delivers targeted energy to devices at a distance. Cota is a patented smart antenna technology that automatically charges multiple devices without user intervention. Its antennas are embedded in transmitters that communicate with compatible receivers.
Walmart has been testing Ossia’s wireless charging technology at its humongous distribution centers. Hatem Zeine, founder and CTO of Ossia, said Walmart’s distribution centers are so big that it’s hard to keep track of all the trucks coming and going. The retailer actually loses track of some of its tractor trailers. Working with the IoT device maker Xirgo, “We created wirelessly powered GPS trackers that are placed on the tractor trailers that come in,” said Zeine. The GPS trackers use embedded Ossia chips.
He said most GPS trackers are powered by batteries, but the batteries are a hassle because they need to be regularly removed and recharged. With Ossia’s technology the trackers are powered wirelessly at a guard shack. They hang in a cabinet without wires and are changed by an Ossia Cota Forever Tracker at a distance of about 4-5 feet. It’s designed for mass charging of many IoT asset trackers, simultaneously and automatically. Each tracking device receives about 2W of radio frequency power when being charged.
Guards at the entrance of the distribution center place a tracker on each truck so its whereabouts are always known. When the truck leaves the distribution center, the GPS tracker is removed and placed in the guard shack where it is again wirelessly charged. The power travels over T-Mobile’s narrowband IoT network.
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“Walmart is a paying customer, and this is something we’re rolling out as we speak,” said Zeine.
Another company that’s making inroads in power-through-the-air technology is Powercast. The company’s wireless charging technology uses broadcasted RF energy (radio waves) converted into DC power.
“The RF we use is very similar to what your cell phone puts out,” said Powercast COO and CTO Charlie Greene. “There’s a transmitter with an antenna that sends out the RF energy and a receiver and antenna that captures it that goes to our chip.”
Greene said most of Powercast’s industrial deployments to date have been in sensors. It’s particularly effective for sensors on rotating machinery that can’t run wires because it’s, well, rotating. Powercast’s technology beams the energy to the sensor device for battery-free power. It’s also helpful in situations where the environmental temperature is too high for a battery.
One Powercast transmitter can power many receiving sensors. Its chips, transmitters and development tools are sold through companies such as Arrow Electronics, Mouser and Digi-Key.