Category Archives: laptops

How To Turn A Standard LCD Monitor Into A Touchscreen For $5

How To Turn A Standard LCD Monitor Into A Touchscreen For $5

Current solutions for enabling touch interaction on existing non-touch LCD screens required adding additional sensors to the interaction surface, but no more!

By using a $5 sensor which plugs into a power socket and some clever software, a non-touch LCD screen is now able to discern between five different gestures.

Full-hand touch
Five-finger touch
Hovering above the screen


As you can see in the video above, there is some touchscreen latency, but for a $5 solution, it works pretty darn well!

The average detection rate is presently 96.4% and it would be higher, but the hard-to-detect hover and push gestures drag it down.

The EMI (Electro Magnetic Interference) caused by a hand placed a few inches away from an LCD monitor is almost infinitesimal.

How It Works

The electricity running through the wires in your house has a unique electromagnetic signature.

And there is a carrier wave introduced by the power company and your nearby substation, and every single kink and switch along the way modulates the electro-magnetic signature, and it’s therefore unique.

When an EMI sensor is plugged into any wall socket, it reads your house’s EM signature and is also very quickly able to detect changes in the signature.

Obvious changes occur when a device is switched on or off, but it also turns out that simply moving your hand close to an LCD monitor also alters your house’s EM signature.

Developed by Ubiquitous Computing Lab, University of Washington

Lead Researchers: Ke-Yu Chen, Gabe Cohn, Sidhant Gupta, Shwetak Patel

ubicomplab have some other really interesting products too which you might want to check out.