There are some interesting things said in that USA Today post.
Asked why the battery percentage didn’t appear to increase rapidly, Perry shakes her head.
“You’re thinking about it the wrong way, this is about a paradigm shift,” she says. “If you’re moving from your car to a coffee shop to work and your phone is charging while you’re using it, it’s no long about what percentage you’re at. You could stay at 1% all day.”
This seems to be implying that uBeam have accepted that the charging power will be pretty low - particularly with multiple devices, and are trying to convince people that as long as you can get enough to match the phone's idle dissipation, the product works.
n a cramped basement office, Perry and a number of colleagues stood in front of another boxy ultrasound transmitter outfitted with an infrared camera vision system programmed to track multiple phones at once. As long as a phone in its case didn’t tilt more than 45 degrees, in other words sufficient for checking messages, the charging icon remained lit.
The tracking system could be very simple - perhaps a cheap camera module tracking IR LEDS on the receivers. Most cameras can see IR LEDS fine. It could be as simple as seeing a flashing code on a pixel on the camera and time multiplexing some power in that direction. By using multiplexing, tracking a large number of devices would be simple. A tracking system like this could even be implemented on an Arduino.
Perry flipped the switch on a large white box, about the size of a ceiling tile. A quiet hum filled the conference room as the entrepreneur asked her visitor to pick up the phone and hold it in front of the box about about four feet away.
When was the last time you heard a hum from a modern power supply? Have they got a massive transformer or is the hum the sound of powerful cooling fans?
If uBeam have developed a cheap high powered dense ultrasonic array, that could possibly be worth more then the $26 million for other uses, even if it is ultimately useless for power charging. That might be the game that is being played.