ComSonics, a company specializing in cable leakage detection, is working on a device that would sense when drivers are texting, the Virginian-Pilot reports. The Virginia newspaper suggests the final product, designed for police to use, might look something like the “radar gun” gadgets that police currently use to log drivers’ speed and give out tickets. The text-sensing device looks for the radio wavelengths that phones use to send and receive SMS messages. Busted!

The device will even be able to distinguish between the radio waves used by texts and the waves used by calls, which are of a different frequency, ComSonics manager Malcom McIntyre told the Virginian-Pilot. That ability would be useful in Virginia and many other states, where it’s legal for adults to talk on a cellphone while driving, but not to text. (Which seems silly. Research has found that having phone conversations while driving is dangerous, too.) It’s unclear, however, how the device will be able to distinguish between texting on the part of the driver, versus passengers in the same car.

ComSonics now makes a number of devices that detect electromagnetic waves, including a few radar-gun-shaped things that find signal leaks in cables.