Japan's Murata Manufacturing has developed a tiny sensor that, if embedded in a computer or tablet device, allows the user to swipe and zoom without touching the display panel.
The sensor isn't much bigger than the tip of a ball pen and has three infrared light sources and a sensor inside. The three lights are arranged in a triangular "v" pattern and pulse briefly on and off in sync with one another so more than one light is never on at the same time.
It's this triangular arrangement and timing that makes gesture detection possible.
Consider a swipe from right to left, as a tablet user might make when turning the page of a book or jumping to the next photo in an album.
When the user's hand is brought over the sensor, infrared light from the right-most of the light sources is reflected by the hand first, followed by light from the source at the bottom of the "v", then light from the left-hand most source.
By analyzing the order the sensor can determine it was a swipe from right to left.
Swipes from left to right, up to down or down to up each have their own signature and can be easily detected.
Because the sensor is measuring reflected light, it's also possible to detect the number of fingers used to swipe. In the case of a two-fingered swipe, there will be a tiny drop in reflected light caused by the gap between the fingers because, for a moment, the light is being reflecting from further away.
The device's ability to perceive depth, which Murata says works up to about 10 centimeters away, can also be used to detect whether a hand is bring brought closer to the sensor or being moved away.
In a demonstration of the sensor at Japan's Ceatec exhibition, that detection was being used for a simple zoom control.
Beyond the detection of user motion, the same sensor can be employed to detect ambient light, motion and proximity, said Murata.
The device is still a prototype and the company says its eventual form will depend on customer wishes. Mass production is also dependent on getting orders from customers.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is firstname.lastname@example.org