Arduino is an open-source electronics platform based on easy-to-use hardware and software. Arduino boards are able to read inputs - light on a sensor, a finger on a button, or a Twitter message - and turn it into an output - activating a motor, turning on an LED, publishing something online. These activities are designed to introduce students to programming and prototype circuits using the free online circuit building software found on tinkerCAD.com.For each circuit activity, students are provid