Matthew Nifield, 33, invented the phone application, called White Noise Ambience, to send his twin daughters Maddie and Gwen to sleep after noticing that relaxing sounds would get them to nod off.
And, it is a worldwide sensation with more than 250,000 parents using it, the 'Sunday Express' reported.
Moreover, the application has earned him 60,000 pounds a year. Now, he's moved from Cardiff to Silicon Valley in California where he is creating more products.
"I've been overwhelmed by the response. There's been loads of downloads in the United States and the UK. But it has also proved very popular in Australia, Japan and South Korea," Nifield said.
