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Tue, Dec. 10

Column: The most revolutionary device invented for tennis since the rubber ball
'My Point'

This past year and now just getting the press it deserves, Gregoire Gentil a Frenchman and inventor who now resides in Palo Alto, California, came up with a solution to the common man’s problem of calling their own lines.

The catalyst was his own love for the game and the frustration of nasty line call spats. Being an inventor and turning his own living room into a laboratory with a 3-D printer and soldering station he created an economical machine he calls “In/Out.”

This machine attaches to the top of the net post with a simple plastic strap and two small cameras looking to one side and the other has three features. It lets you know within 99 percent accuracy if your shots or serves were in or out with a green or red light as well as a series of beeps. It takes a HD video where you can learn from your mistakes and it shows where each shot landed, the speed of the ball, the amount of spin and more.

It runs on a standard battery and also has USB connection.

What normally has cost $60,000 to $80,000 up to now to monitor calls and give data feedback and has a little more accuracy than “In/Out” can now be purchased for $199.00.


The same technology that is being used by Tesla and Google autonomy to know where pedestrians are, when the light is red or green - is what Gentil has put into this special tennis machine.

The drawback might be in doubles when a player steps in the way of the camera and blocks the view of a landing ball - the solution is to have a camera mounted on the other net post (two In/Out devices) to alleviate that situation.

This new invention is being made in China and the first batch are currently being sent out. The second order will be going out after the first of the year.

It looks as if he will be stretching this technology into many other sports related fields which will be very exciting to see take place.

Can’t wait to see the “In/Out” on our own courts soon.

Chris Howard is a local USPTA Tennis Professional with over 45 years in the racquet and fitness industry. He can be reached at 928-642-6775 or

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