The students designed a sound emitter mounted behind the backboard that sends out low pulse tones to help players locate the shooting target. A smaller sound emitter, embedded in an otherwise standard basketball and powered by five 3-volt button-size batteries, sends out a higher, continuous tone to tell players where the ball is. A remote control turns the backboard emitter on and off when needed.
"There have been other attempts to do this in the past, but usually they involved things that screwed up the bounce and weight. The goal here was to get it within size and weight," said Mike Bullis, business services development manager for Blind Industries and Services of Maryland. "Many blind kids don't have these kinds of recreational opportunities."
Some kinks on the prototype still need to be worked out, according to Bullis, who himself is blind and sank shots with the ball at a recent demonstration. The sound pitch inside the emitter in the basketball needs to be lowered for the comfort of players and to avoid echoes, which could mislead a shooter, he said. Bullis added that he will start to contact sports manufacturers to gauge their interest in developing basketballs, soccer balls and other equipment.
The project emerged out of a two-semester mechanical engineering course. Two of the students, Alissa Burkholder and Ashanna Randall, played on the women's basketball team at the university. The third student was Steve Garber. They all graduated earlier this month.
One of the engineering challenges involved getting the sound emitter inside the basketball. The three students found that a particular basketball from Spalding, the Infusion, comes with a small, internal cylinder that houses a pump. The pump slides out of the basketball, out of the spot where one inserts the inflating needle on most basketballs. The cylinder resembles a plunger from a small syringe.
The students cut open some of the basketballs to determine how the cylinder worked. They also contacted Spalding, which provided five cylinder-less Infusions. The cylinder cavity proved big enough to house a tube containing the batteries and the sound emitter.
Currently, only a high-pitched sound emitter will fit in the cavity. "It is the kind of thing that, if you listen to it long enough, it will make you want to kill someone," Bullis said. The students are now trying to figure out how to slot in a small speaker system. The challenge there is keeping battery consumption down.