I absolutely love the Internet Of Things and everything do-it-yourself, and so in today's world of fast communications, getting things accomplished in record time pays dividends! If you would like to build an app for your Arduino project, you can do this quick and easy in 5 minutes flat!

You don't have to use a Bluetooth module and MIT's app inventor to create a wireless serial link between your smartphone and an Arduino board. The solution that allows you to control an Arduino board with a smartphone in 5 minutes or less is called Blynk.
Blynk allows you control servos, blink LEDs and get sensor data straight to your smartphone from anywhere in the world. What is really clever about Blynk is that the maker realizes that an smartphone contains many of the components that you would need for an Arduino project like touch screen display and sensors like GPS and accelerometer so why not utilize them?

Blynk consists of three main components 1) apps (for Android and iPhone), 2) a server that handles all the authentication and communication and 3) libraries for the key hardware. Blynk app interface consists of a dashboard area and widget box with a list of widgets.
Let's say you want to control an Arduino bulb with your smartphone. Set an Arduino UNO with an Ethernet shield and connect Pin 8 to relay module. Now go to the Blynk app and pick a widget button and place it anywhere on the dashboard. Each individual widget has its own settings so when clicking on the "button" widget you can give it a name, make it a "switch" or "push" and then select the pin which controls the relay (in this case pin 8). To connect to the Arduino UNO you will need an authentication token, so from the settings on the Blynk app select "Send Token". The authentication token is then sent to your email address.

Now open Blynk sketch in Arduino IDE, enter the authentication token and click upload onto the board. That's it. Clicking the widget button now allows you to switch the bulb on and off on your Arduino....all in less than a minute!

Blynk's intuitive interface is great for newbies though pros can fully customize the dashboard to support a most complex project so it's a win win solution for everyone.