Hoopfit

A machine that catches a basketball under the hoop and passes it back to the player, so one person can practise shooting alone.

What it had to do

1. Pass the ball anywhere on the court, from 1 metre out to the 3-point line at 7 metres.
2. Turn to follow the player: a sprint round the free-throw line takes 2.2 seconds, so it had to turn 180 degrees in 2.2 seconds.
3. Aim within 2 degrees, so a pass lands within 23 cm of a player 7 metres away.
4. Keep up with 1,000 passes an hour, one every 3.6 seconds.
5. Catch every ball, made or missed.
6. Weigh about 45 lb, fold into the boot of a small car, and be set up by one person.

Launching the ball

I compared five ways to throw a ball: two wheels side by side, two wheels one above the other, a slingshot, a striking arm and compressed air. I built and tested prototypes from February to August 2022. Two wheels passed well but wore away the surface of the ball, and two motors made the machine heavy. One wheel and a long curved ramp needed one motor, so the battery was smaller and the machine lighter. The ball drops in at the top, and the wheel pushes it along the ramp and out of the front.

Catching the ball

The first versions hung under the rim with a net above them. Then the machine moved to the ground, and a new net funnels every ball down a tube into it. The net folds up, and one person can set it up.

The finished machine

The player shoots. The net catches the ball, made or missed. A tube slows it down, and it drops through a bearing into the launcher. The iPad sees where the player is. The base turns the launcher to face the player, and the wheel sends the ball along the ramp and back. Inside the launcher: a panning base with a stepper motor, a battery, a custom board, the launch ramp, the launch hub motor, side panels, a top cover, the bearing for the net tube, and a carrying handle that holds the iPad Air.