# You (almost) can't be too drunk to miss with this motion-tracking dartboard

Automatic Bullseye, MOVING DARTBOARD
Ever wonder what former NASA engineers do for fun? If they’re like Mark Rober, they spend their time inventing awesome techy gadgets and making YouTube videos about them. Rober’s last effort, spotted by Gizmodo, should be in every bar, pub, and club: a motion-tracking dartboard that guarantees bullseyes.

Your dart has to reach the same wall the dartboard is hanging on, so there are some limitations, but for most players, it shouldn’t be too much of a challenge.

According to Rober, it took him and another former rocket scientist named John more than three years to design, build, and get the kinks out of the dartboard.

There were two major problems to solve. The first challenge was to predict where the trajectory of a dart thrown from the regulation distance would land. The throw occurs in about 200 milliseconds or one-fifth of a second. Apparently, that’s loads of time from a NASA perspective.

Rober and his buddy positioned six Vicon motion-tracking cameras with infrared sensors between the throwing line and the dark board. The cameras coordinate to determine the parabola of the thrown dart and a linked computer does the math to determine the exact two-dimensional coordinates of the spot where the dart will hit.

The darts are regulation models fitted with infrared reflectors so the cameras can track them regardless of what else is in the background.

The second challenge was to figure out how to get the dartboard to move so the bullseye would be in the location where the dark landed. This positioning also has to happen within 200 milliseconds.

Six stepper motors attached to the back of the dartboard with fishing line move it into position. The cameras keep running and the trajectory tracking continues throughout so within the last fifth of a second the board can be repositioned up to 100 times to be in the exact spot.

The final result, as you can see, works perfectly. When Rober took the setup to a local bar for testing “in the wild” the reception was enthusiastic — to the point that one participant hollered, “I used to suck at darts!”

Obviously, they gave that guy the correct dart. Rober also has a dart that will move the board in the opposite direction so no matter how great your shot, you’re guaranteed to miss.

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