Answer:
A technological method is able to cheat at roulette using concealed electronic equipment to measure the roulette wheel speed, ball speed and reference point. Data is feed in to an external computer outside the casino then returned to player to make a bet within seconds of the dealer spinning the wheel. Betting a whole sector of the wheel that the computer predicted the ball would land.
However, be advised that if you are caught using any electronic devices in a casino you will be banned from that casino and most likely all the casinos in that state.