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 piArduino Playgroundi 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 br-A reaction-time game that leverages the Arduino's real-time capabilitiesbr-A tool for etching your own printed circuit boardsbr-A regulated, variable-voltage power supplybr-A kinetic wristwatch winder decked out with LEDsbr-A garage parking assistant that blinks when your vehicle is perfectly parkedbr-A practical and colorful pH meterbr-A ballistic chronograph that can measure the muzzle velocity of BB, Airsoft, and pellet gunsbr-A battery saver that prevents accidental dischargebr-A square-wave generatorbr-A ther