Engineer invents device to detect convicted sex offenders

The father of a 4-year-old boy has invented a machine that triggers an alarm when a convicted sex offender wearing an electronic monitoring anklet approaches.

Dubbed the “electronic anklet detector,” the device rings an alarm when a convicted sex offender wearing an anklet approaches within 30 minutes.

Inventor Hong Gwang-ui, 43, said, “Whenever I watched news on violent sex crimes, I got infuriated as a father,” adding, “After racking my brain over how to prevent sex crimes, I developed this machine.”

Hong is an engineer who helps develop information protection systems for the military.

The mechanism of the detector is simple. Electronic monitoring anklets worn by convicted sex offenders send out a unique radio frequency to the control center every six seconds. Hong`s invention is designed to detect this frequency.

With development completed, the device will be sold online as early as next month. Hong also got approval from the Justice Ministry saying the sale of the detector is not illegal.

"Thus far, people have had no way to know if a convicted sex offender follows a child with bad intentions,” Hong said, adding, “I hope this detector will help prevent sex crimes.”

The inventor plans to sell the gizmo only if a buyer will install it in designated places, including playgrounds and roadsides near schools, because individual ownership of the device could constitute a violation of human rights.

sun10@donga.com