This idea takes those buzzers that you get at bars to a new level/application. The ones that they give you when you order your food, and then they vibrate and flash and make noise when the food is ready to collect.
So what you do is you have 4 of these, which can light up different colours. The coach has the controller, and can select “1” and then “blue” which will make the first ring light up blue. The idea here is that you can make a whole bunch of drills to train players to do certain things. For instance, putting them under a ball and lighting them up just as the player kicks the ball, and having them shout out the colour means that you’re forcing them to keep their head down when kicking a ball. Similarly, by placing them elsewhere or holding them, the player has to look up and shout out the colour. So you can teach them all the habits for “looking”. Another one would be to hang them in each corner of the goal and say to the player that they need to shoot for blue, and then lighting one up at the last second in blue.
I’m thinking they need to be rings so that a ball can fit right through it.