Microsoft Charges Handsets using Light Beams and Cameras

January 19, 2015 by Jeff Shepard

A team of engineers at Microsoft Corp.'s Beijing, China, research laboratory have demonstrated AutoCharge, an approach that automatically locates a smartphone on a desk and charges it in a transparent matter for the user. This is achieved by two techniques. First, it leverages a solar charging, but uses it indoors, to remotely charge a smartphone using a light beam without a wire. Second, it employs an image-processing-based system to detect and track smartphones on a desk for automatic smartphone charging. As a result, AutoCharge is able to largely reduce users' efforts in smartphone charging and significantly improve the user experience.

The Microsoft research engineering team designed and implemented a prototype system of the AutoCharge approach. Experimental results show that the prototype is able to detect the presence of a smartphone within seconds and charge it as fast as existing wired chargers, demonstrating the feasibility of automatic smartphone charging.

“Solar charging is not widely used on smartphones because of several limitations. It works only in outdoor spaces but not indoor spaces. Due to severe scattering, the indoor surrounding light is usually much weaker (two orders of magnitude weaker or even worse) than the sunlight and thus cannot be used to charge a smartphone. Even when users are in outdoor spaces, they usually put they smartphones in a pocket or a bag so that solar charging cannot help,” the Microsoft team reports.

“Furthermore, solar charging heavily depends on the weather condition and time. Solar charging does not work at night or when it is cloudy or rains. By applying solar charging to indoor spaces, we make it work for 24 hours per day, no matter what the weather condition is. To meet the requirements of charging a smartphone, we designed the charger to generate a straight light beam with little scattering so that we can improve the charging efficiency and speed,” the team continued.

“Second, we designed a system of smartphone detection and tracking for automatic smartphone charging. The charger uses a camera to keep monitoring a surface such as a desk in office. When a smartphone is put onto the desk, the charger can quickly detect the presence of the smartphone. If the smartphone is able to be charged by a light beam and its battery is low, the charger starts to charge the smartphone. The charger uses a rotating motor to adjust the direction of its light beam so that it is able to accurately project the light beam on the smartphone. After the battery is full, the charging stops. The whole process is completely automatic and transparent for the user. In addition, the system is able to support multiple smartphones. If there are multiple smartphones on the same desk, the charger can charge them one by one,” the team elaborated.

“We have implemented a prototype AutoCharge system. Experimental results show that our prototype implementation is able to quickly detect a smartphone on a desk in various settings and charge it as fast as existing wired chargers. Despite that our prototype implementation is still far away from a real product and may be further improved in many aspects, we have demonstrated the feasibility and made a significant step towards automatic smartphone (and other mobile devices) charging,” they concluded.