A small gadget weighing just 8g could be the key to helping a tennis player find his master stroke.

All he needs to do is clip the dollar coin-size gadget, called Qlipp, to the strings of his tennis racket, in the same way a dampener is attached to control string vibrations.

Then, just before a game, he needs to push a button, and the accelerometer and gyroscope in the gadget will whir to life.

They record data such as stroke type, swing speed and ball spin. They can also detect the part of the racket used to hit the ball.

The data is then transmitted via Bluetooth to the Qlipp app on the player's mobile phone, in real time.

Players can also shoot a video of the game using the app, which syncs the visual data with the other measurements.

Such data will give players a better idea of their game and where improvements can be made, said Dr Donny Soh, who developed the technology as a scientist at the Agency for Science, Technology and Research (A*Star).

Dr Soh, 37, now markets Qlipp with his partner, Mr Cen Lee, 36, through 9 Degrees Freedom, an A*Star spin-off company of which he is chief executive.

Dr Soh said: "A common mistake many players make is to hit the ball fast but inaccurately, causing it to miss the sweet spot - usually the centre of the racket.

"Our data will advise the player to slow down and take better aim before speeding up again."

Each Qlipp device costs US$129 (S$182) although the current pre-order price is US$99. There have been pre-orders for more than 900 units since the product was launched in June this year. They will be shipped this month.

Dr Soh started developing Qlipp in 2011, after working for two years on a tennis virtual reality programme at A*Star's Institute for Infocomm Research.

Dr Soh, who graduated with a PhD in computer sciences from the Imperial College London in 2009, decided to port the technology over to the actual game when he saw the market potential for a performance-measuring device for tennis.

So 9 Degrees Freedom was set up to turn research into application.

He noted that while there are other similar sensors on the market, such as Babolat Play Pure Drive smart racquet and Zepp Tennis, Qlipp is attached to the strings instead of the base of the racket.

Avid tennis player Marc Koh, 42, said having the gadget on strings provides more accurate data on the racket head speed, the spin imparted by the strings on the ball and also the contact point on the string bed relative to the sweet spot.

Mr Koh, a currency derivatives trader who had managed the Singapore Tennis Association's full-time tennis programme for four years, added: "Qlipp allows players and coaches to scrutinise technical details of the player... (and) is a must-have if a player wants to get into details."

The next step is to incorporate a social network aspect to Qlipp, Dr Soh said.

In the future, he also hopes to expand by adjusting the algorithms in the software so that the gadget can be used for other sports, such as squash and golf.

"But we are taking baby steps. There are an estimated 43 million tennis players in the world, and we hope to reach them," he said.