Howard Stapleton's device, which emits ultrasonic sound waves that can normally be heard only by people aged under 25, has captured the public imagination at a time when confronting yob culture is one of the contentious political issues.
In the course of a week, he has appeared on national breakfast television and been profiled in newspapers, and is now in the final stages of negotiating a major order with a chain of convenience stores.
He claims the device, named the Mosquito after the flying insect's notorious whine, does not cause pain but is so irritating that young people will not linger in an area where they can hear it.
Explaining the rush of interest in his product, Mr Stapleton said, 'With this trouble in France, it looks like we are descending into gradual anarchy. They have picked up on a novel idea that's really needed.'
At present, the devices are put together at the Servonetic Control (Instruments) plant at Taffs Well.
The plan is that revenue from this project will fund a much more ambitious invention. This is a security system for the fences around construction sites which will be detect if a vibration is caused by someone climbing over it.
Present systems can be set off when a football hits the fence, causing many alarms to be ignored.