![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/RGB-LED-App-GIF.gif?resize=480%2C270&quality=100&strip=all&ssl=1\")
<\/p>\nIn this project you’re going to build an Android app to control the color of an RGB LED with a smartphone via Bluetooth.<\/p>\n
You’re going to build the Android app using a free web based software called MIT App Inventor 2. This is a great project to learn how to interface the Arduino with a smartphone.<\/p>\n
<\/p>\n
If you’re not familiar with RGB LEDs, read\u00a0the following post:\u00a0How do RGB LEDs work?<\/strong><\/a><\/p>\n Download Android Apps for Arduino with MIT App Inventor 2<\/a><\/strong><\/p>\n Here’s a complete list of the parts required for this project:<\/p>\n Additionally, you also need a smartphone with bluetooth.<\/p>\n You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p> The Android App will be created\u00a0using a free web application\u00a0called\u00a0MIT App Inventor<\/a>. MIT App Inventor is a great place to get started\u00a0with Android development, because it allows you to build simple apps with drag-n-drop.<\/p>\n You need a Google account to sign up for MIT App Inventor and here\u2019s the login page: http:\/\/ai2.appinventor.mit.edu<\/a>.<\/p>\n After login in go to\u00a0Projects >Import project (.aia) from my computer<\/strong> and upload the .aia file. Click here to download the .aia file.<\/a><\/strong><\/p>\n After uploading the .aia file<\/a>. You’ll see the application on the MIT App Inventor Software.<\/p>\n With MIT App Inventor you have 2 main sections: designer<\/strong> and blocks<\/strong>.<\/p>\n The designer is what gives you the ability to add buttons, add text, add screens and edit the overall app look. Int the App Inventor software the app looks like this:<\/p>\n The app looks different in the software and in your smartphone. This is the how the app looks in our smartphone:<\/p>\n Then, you have the blocks section. The blocks sections is what allows to create custom functionality for your app, so when you press the buttons it actually does something with that information. These are the blocks for this app (click on the image to zoom):<\/p>\n To install the app in your smartphone, go to the Build<\/strong> tab. Simply follow the installation wizard to install the App and it\u2019s done!<\/p>\n Download or copy the following code to your Arduino IDE, and upload it to your Arduino board. Make sure you have the right Board and COM port selected.<\/p>\n Note<\/span>: before uploading the code, make sure you have the TX and RX pins disconnected from the bluetooth module!<\/strong><\/p>\nParts Required<\/h2>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/parts.jpg?resize=700%2C474&quality=100&strip=all&ssl=1\")
<\/p>\n\n
![](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/10\/header-200.png?w=1200&quality=100&strip=all&ssl=1\")
<\/a><\/p>\nCreating the Android App<\/h2>\n
![\"import\"](\"https:\/\/i0.wp.com\/rntlab.com\/wp-content\/uploads\/2016\/10\/import.png?w=1200&quality=100&strip=all&ssl=1\")
<\/p>\nDesigner<\/h3>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/designer.png?resize=1200%2C524&quality=100&strip=all&ssl=1\")
<\/p>\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/Screenshot_2017-04-23-10-05-47.png?resize=259%2C461&quality=100&strip=all&ssl=1\")
<\/p>\nBlocks<\/h3>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/blocks.png?resize=1055%2C457&quality=100&strip=all&ssl=1\")
<\/a><\/p>\nInstalling the App<\/h3>\n
![\"build\"](\"https:\/\/i0.wp.com\/rntlab.com\/wp-content\/uploads\/2016\/10\/build.png?resize=416%2C122&quality=100&strip=all&ssl=1\")
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Code<\/h2>\n
\/*\n * Rui Santos \n * Complete Project Details http:\/\/randomnerdtutorials.com\n *\/\n\n#define max_char 12\nchar message[max_char]; \/\/ stores you message\nchar r_char; \/\/ reads each character\nbyte index = 0; \/\/ defines the position into your array\nint i;\n\nint redPin = 11; \/\/ Red RGB pin -> D11\nint greenPin = 10; \/\/ Green RGB pin -> D10\nint bluePin = 9; \/\/ Blue RGB pin -> D9\n\nint redValue = 255; \/\/ Red RGB pin -> D11\nint greenValue = 255; \/\/ Green RGB pin -> D10\nint blueValue = 255; \/\/ Blue RGB pin -> D9\n\nString redTempValue; \/\/ Red RGB pin -> D11\nString greenTempValue; \/\/ Green RGB pin -> D10\nString blueTempValue; \/\/ Blue RGB pin -> D9\n\nint flag = 0;\nchar currentColor; \n\nvoid setup() {\n pinMode(redPin,OUTPUT);\n pinMode(bluePin,OUTPUT);\n pinMode(greenPin, OUTPUT);\n \/\/ initialize serial communication at 9600 bits per second:\n Serial.begin(9600);\n}\n\nvoid loop() {\n \/\/while is reading the message \n while(Serial.available() > 0){\n flag = 0;\n \/\/the message can have up to 12 characters \n if(index < (max_char-1)){ \n r_char = Serial.read(); \/\/ Reads a character\n message[index] = r_char; \/\/ Stores the character in message array\n if(r_char=='R'){\n currentColor = 'R';\n redTempValue = "";\n }\n else if(r_char=='G'){\n currentColor = 'G';\n greenTempValue = "";\n }\n else if(r_char=='B'){\n currentColor = 'B';\n blueTempValue = "";\n }\n if(currentColor == 'R' && r_char!='R'){\n redTempValue += r_char;\n }\n else if(currentColor == 'G' && r_char!='G'){\n greenTempValue += r_char;\n }\n else if(currentColor == 'B' && r_char!='B'){\n blueTempValue += r_char;\n }\n index++; \/\/ Increment position\n message[index] = '\\0'; \/\/ Delete the last position\n }\n \n }\n \n if(flag == 0){\n analogWrite(redPin, 255-redTempValue.toInt());\n analogWrite(greenPin, 255-greenTempValue.toInt());\n analogWrite(bluePin, 255-blueTempValue.toInt());\n \/*Serial.print('R');\n Serial.println(redTempValue);\n Serial.print('G');\n Serial.println(greenTempValue);\n Serial.print('B');\n Serial.println(blueTempValue);\n Serial.print("MESSAGE ");*\/\n Serial.println(message);\n flag=1;\n for(i=0; i<12; i++){\n message[i] = '\\0';\n } \n \/\/resests the index\n index=0; \n }\n\n}\n<\/code><\/pre>\n\t
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/rgb_led_controller.png?resize=404%2C529&quality=100&strip=all&ssl=1\")
<\/p>\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/circuit.jpg?resize=700%2C394&quality=100&strip=all&ssl=1\")
<\/p>\n![\"screenshot_2016-10-09-15-14-52-copy\"](\"https:\/\/i0.wp.com\/rntlab.com\/wp-content\/uploads\/2016\/10\/Screenshot_2016-10-09-15-14-52-Copy.png?resize=284%2C505&quality=100&strip=all&ssl=1\")
<\/p>\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/Screenshot_2017-04-23-10-05-47-Copy.png?resize=286%2C509&quality=100&strip=all&ssl=1\")
<\/p>\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/04\/linvor.png?resize=390%2C86&quality=100&strip=all&ssl=1\")
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