Was reading some more about tactile projection and vibrotactile displays, and I came across the ‘eudaemonics‘ group, utterly nerdy precursors of wearable computing. From Wikipedia: “Since the calculations were very complicated, they decided to build a computer customized for the purpose of being fed data about the roulette and the ball and to return a prediction of which of the roulette’s octants the ball would fall on. The computer was concealable, designed to be invisible to an onlooker. It was small enough to fit inside a shoe. The input was by tapping the big toe on a micro-switch in the shoe. Then an electronic signal was relayed to a vibrotactile output system hidden behind the shirt, strapped to the chest, which had three solenoid actuators near the stomach which would indicate by vibrating either which of the eight octants of the roulette to place a bet on, or a ninth possibility: to not place a bet.”

Steve Mann has pictures of the actual computer: