Attempting to make a Cornhole score board with 21 lights that light up at each button push. At the end of the chain i want it to shut off the lights so there is none. I am very new to this and have only gotten to the research part. Any help i can get will be amazing. Thank you.
Remember that each little LED consumes a small amount of power, so when you multiply that small amount by 42 in total it starts to add up. Also you need to be mindful that you don't overload the microcontroller pins or its power supply when driving lots of LEDs at the same time.
Before you know it you will be building button walls like these: 
