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The toy train chugged endlessly along the Wi-Charge booth... until I put my hand over it to block the laser that was transmitting power to it.

It's certainly impressive tech, especially considering it's the only thing being demoed at the booth. It was surrounded by signs stating clearly that there were no batteries powering the toy train.

It's not the first time we've seen Wi-Charge's tech in action -- we had a preview in 2015 -- but it feels a lot more refined after two years. The receivers look cleaner and the power delivery mechanism looks smaller. How it works is simple: The transmitter sends energy through an infra-red laser to the receiver, where a photovoltaic cell converts the light to energy.

Each projector can be paired with three devices at an 8-meter range and can transmit up to 3W of power, enough to keep your phone charged. Wi-Charge expects public places like cafes will have multiple transmitters to keep all of its customers' devices charged as they sip a cup of joe without the use of messy wires.

However, if line of sight to the transmitter breaks (because you use your hand to cover the receiver), the system will take some time to reacquire a lock.

Aloysius Low/CNET

Wi-Charge's Alex Shulman told CNET that power efficiency is obviously not as good as cables or Qi, but the advantage is that you don't necessarily have to be at a specific spot to charge your devices. In the future, it's possible to use its technology to wirelessly power devices like home security cameras.

Check out more of CNET's Computex 2017 coverage here.