You ve mastered the basics, conquered the soldering iron, and programmed a robot or two; now you ve got a set of skills and tools to take your Arduino exploits further. But what do you do once you ve exhausted your to-build list? Arduino Playground will show you how to keep your hardware hands busy with a variety of intermediate builds, both practical and just-for-fun. Advance your engineering and electronics know-how as you work your way through these 10 complex projects: A reaction-time game that leverages the Arduino s real-time capabilities A tool for etching your own printed circuit boards A regulated, variable-voltage power supply A kinetic wristwatch winder decked out with LEDs A garage parking assistant that blinks when your vehicle is perfectly parked A practical and colorful pH meter A ballistic chronograph that can measure the muzzle velocity of BB, Airsoft, and pellet guns A battery saver that prevents accidental discharge A square-wave generator A thermometer th