Wireless charging has liberated some users from requiring cords and outlets, but the technology comes with limits, as devices must be within close proximity to RF-based or magnetic-induction wireless charging pads to receive energy from a relatively short-range magnetic field. While there are solutions for longer-range RF transmissions, they require a large antenna on the receiver, which is not applicable for small consumer electronic devices.
Israeli technology company Wi-Charge has released an alternative known as the AirCord, which consists of infrared (IR)-based transmitters and receivers that power devices over the air at a distance, using infrared transmissions. The solution, for which the company says it has more than 100 patents, consists of an IR emitter transmitting highly focused beams that can locate a receiver built into a battery-operated device, and then transmit that power as long as the device is within range and line of sight. That means, for instance, an AirCord could power all devices within a room-sized area, but only via targeted IR transmissions, as opposed to blanketing a space with wireless energy.
The AirCord can be plugged into a power source with either a USB connection, an outlet or Power over Ethernet (PoE), and it will then send out a directional beam of infrared light, according to Ori Mor, Wi-Charge’s co-founder and chief business officer. A receiver on the enabled device, such as a smartphone or tablet, then converts that beam into electricity. The receivers are about the size of a thumb, Wi-Charge reports, and are being built into consumer electronic devices for some early applications. The company says it intends to develop future versions that are even smaller so that they could be built into everything from smartphones to smart watches.
Charging at a Distance
To create a wireless charging zone, users can plug the IR AirCord transmitter into a USB port. The device not only transmits IR beams, but is designed to automatically identify receivers based on their IR properties. The IR beam sent by the transmitter targets a specific device for charging, and it can follow that device as it moves. The AirCord receiver of the phone or tablet then converts the collected IR energy to electricity and charges any internal rechargeable battery or supercapacitor, while sending back device telemetry, such as battery status or usage statistics.
The transmitter can power multiple devices at the same time, using beam hopping. The company expects the technology to be used initially at offices, in public areas, at supermarkets, on production floors, and at shopping centers and restaurants, and to then follow in mainstream consumer products. The system can be set up with a single transmitter or a network of them, which will communicate through a cloud-based server and allocate power to different devices, based on each one’s requirements.
Wi-Charge was launched by veterans from the Israeli military intelligence’s technology unit. Mor recalls, “We asked ourselves a simple question: ‘Can over-the-air charging be done, based on physics and regulations?'” The team concluded that it could, but that the fundamental building blocks for such a system were still missing. Eight years of development then followed.
According to Mor, Wi-Charge chose a different approach from that of most wireless power companies that typically provide magnetic induction or RF-based power. “We chose infrared,” he explains, “because it allows us to deliver more power, over longer distance, to smaller receivers.” Because a smaller receiver can be used, the device could more easily be embedded into most consumer electronic devices.
To test the technology, the company built a system with model trains that contained no power source, but instead used Wi-Charge receivers. As the receivers captured the IR energy from an AirCord device, they converted energy to propel the train forward. The transmitter then tracked the receiver’s movements and continued to power the train as it moved along the tracks. The result was a model train without the need for batteries. The company began miniaturizing the transmitter and released it in late 2022.
Commercialization Leading to Applications
The technology has since been deployed in Brazil, Canada, Germany, Hungary, Israel, Malaysia, Mexico and the United States, and it is now available worldwide. The early applications for the AirCord are in commercial spaces for specialized devices that require power, but for which batteries are neither sustainable nor practical. For instance, some retailers are using the system to power advertising displays, enabling them to provide content at the sites where specific products brands are sold or displayed.
With a low-cost wireless charging solution, Mor says, businesses can deploy small displays at strategic locations where their content will be of most value. “The best place to advertise is in the store and next to products,” he states, “so the lack of power at the shelf creates missed opportunities for retailers.” Electronic shelf labels, for instance, consume roughly 40 or 50 microwatts of power, and they traditionally had depended on batteries that need to be replaced. That can be challenging for stores, where tens of thousands of such labels may be in use. Wi-Charge can support power rails on shelves on which labels are powered to enable retailers to update daily promotions and check inventory.
Ori Mor
Another early use case is a smart lock that is powered by the AirCord in a doorway. Alfred Inc., a Canadian smart lock company, is offering locks that are wirelessly charged by Wi-Charge. The system captures IR power to enable wireless access to authorized individuals, such as guests at a hotel, Airbnb or resort, or for tenants in an apartment building or employees at a worksite. The company has also created reference designs for a gaming controller that has a receiver built inside, allowing gamers to play without running out of power. Another reference design is a wirelessly charged electric toothbrush charger, built to eliminate the need for cords in bathrooms.
Wi-Charge offers an interim solution that would enable phones or tablets to be charged even if AirCord receivers are not yet built into such devices. For example, a Wi-Qi Charging Pad receives power from the transmitter and provides traditional electro-magnetic power to devices placed on the pad. Because IR requires a line of sight, the charging signal can be blocked. When line of sight is interrupted, Mor says, the device continues to work uninterrupted, using existing stored power. Then, once line of sight has been restored, charging resumes.
At present, Wi-Charge reports, the transmitter can accomplish a 10-meter (33-foot) range without power dropping. Transmission only takes place if there is a receiver within sight, and thus no stray radiation can interfere with other devices. Thus far, the company says its customers have been solution providers. However, Mor notes, Wi-Charge is working with original equipment manufacturers, as well as some utility companies that could offer wireless power as a service to their customers in the future.
For instance, a utility company could provide the transmitter and, if receivers were built into devices, the wireless charging could be accomplished automatically at a home or business. To save power, the system can turn a transmitter off when there is no traffic, either based on the presence of people or by using timers. Wi-Charge’s long-term expectation, Mor says, is that the receivers will be built into most mobile devices and for other applications with limited battery life for unlimited and seamless power.
Key Takeaways:
- Wi-Charge’s infrared wireless charging technology is aimed at electronic devices that require dedicated chargers to remain powered.
- The company’s solutions include wire- and battery-free electronic shelf labels and displays, as well as faucets in public bathrooms and other solutions, to bring targeted power to a device.