I Built a LEGO Robot that Catches Falling Balls

Building a LEGO robot that can react in real-time to a ball falling in front of it, and move to catch it before it hits the ground, was an idea so ambitious and so exciting that I simply had to give it a try. To make this work, the plan was to let the ball first bounce on a glass plate in front of the robot. By detecting where on the plate the ball bounced, the robot could then move to that spot to catch it before it hits the ground again. After testing each type of the LEGO sensor available, I settled on using two sound sensors to triangulate the position of the ball on the plate. This led to a ton of interesting problems and challenges, but after a long development process my ball-catching robot was finally working, and had quite impressive accuracy. Enjoy the video! Graphs created using Desmos 3D Graphing Calculator. Creative Commons “Attribution-ShareAlike” license (CC-BY-SA-4.0).