Controlling websites with an Arduino is like magic. Suddenly little bits of hardware can control all kinds of games and interfaces on screens. And building a UI for your electronics becomes trivial too. This is a talk for anyone who’s ever tinkered with hardware or web design, and wants to join the physical to the digital. During this talk I will explain the basic techniques of keyboard emulation and using the Javascript Web Serial and Web Bluetooth APIs. To make it fun, and introduce some peril, I will demo all of the techniques live: controlling the Google Chrome Dino game by jumping up and down on stage, making a musical instrument from stretchy rubber and allowing audience members to connect to a set of handbells from their phones. Along the way will be plenty of tips on what to buy and what to avoid, I’ll demystify some of the complexity around Bluetooth and USB, and share several ideas for how to use this to cause mischief amongst friends, colleagues and enemies. I have done this before, but only once. Fingers crossed.