The download button opens the iTunes App Store, where you
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From Spark Labs, Inc.:
Get connected and start building your Internet of Things project right away with Particle, the companion app to the Photon, a tiny but powerful Wi-Fi development board from the team at Particle (formerly known as Spark). Your Photon and this app are all you need to get started with your project or prototype; the kit comes pre-loaded with our firmware libraries and is connected to the cloud out of the box.Download Particle app to easily connect your Photon to a Wi-Fi network in a few simple steps. The app will take you through the entire set-up process step by step until the LED on your board is breathing cyan - indicating it's connected and ready to be programmed!Along with getting connected, app contains 'Tinker', a quick start sandbox that will help you get your prototype or project up and running in minutes. Tinker exposes basic pin functions through our API, allowing you to read sensor data and blink LEDs by just tapping a pin name on screen -not a single line of code needed. It provides an intuitive environment for tinkering and prototyping even if a Photon is the first piece of programmable hardware you've ever picked up!