In this final lesson on Lego EV3 we’re going to use everything we’ve learned to build a reaction time tester. You’ll also learn about Timers, which is used to measure how much time has gone past. Basically the program will play a sound at a random time, and you will need to press a button as soon as you hear the sound, after which the program will report back to you what your reaction time is, and store it inside a text file. Enjoy!