Introduction

In this article, I am going to explain about controlling the LED in the Keypad app by an Android app. It will be run in a real-time process for the home application.
Software Requirement
  1. Arduino Uno
  2. LEDs
  3. Bread Board
  4. Hook-Up Wires
Connection from Arduino Board to LEDs
Leds Arduino Board
Led1 11
Led1 12
Led1 13
Led1 14
Programming
  1. #define CUSTOM_SETTINGS
  2. #define INCLUDE_KEYPAD_SHIELD
  3. /* Include 1Sheeld library. */
  4. #include <OneSheeld.h>
  5. int A, B, C, D; //vaiables with names of buttons in keypad
  6. /* A name for the LED on pin 8. */
  7. int yellow = 8;
  8. /* A name for the LED on pin 9. */
  9. int green = 9;
  10. /* A name for the LED on pin 10. */
  11. int white = 10;
  12. /* A name for the LED on pin 11. */
  13. int red = 11;
  15. void setup()
  16. {
  17. /* Start communication. */
  18. OneSheeld.begin();
  19. /* Set LEDs as output. */
  20. pinMode(yellow, OUTPUT);
  21. pinMode(red, OUTPUT);
  22. pinMode(green, OUTPUT);
  23. pinMode(white, OUTPUT);
  24. }
  26. void loop()
  27. {
  28. Keypad.setOnButtonChange(&lightLed);
  29. }
  30. void lightLed (byte rowNumber , byte coloumnNumber)
  31. {
  32. /* If keypad's button A is pressed. */
  33. if(Keypad.isRowPressed(0) && Keypad.isColumnPressed(3))
  34. {
  35. A = 1; // press A
  36. B = 0;
  37. C = 0;
  38. D = 0;
  39. }
  41. else if(Keypad.isRowPressed(1) && Keypad.isColumnPressed(3))
  42. {
  43. A = 0;
  44. B = 1;// press B
  45. C = 0;
  46. D = 0;
  47. }
  49. else if(Keypad.isRowPressed(2) && Keypad.isColumnPressed(3))
  50. {
  51. A = 0;
  52. B = 0;
  53. C = 1; // press c
  54. D = 0;
  55. }
  57. else if(Keypad.isRowPressed(3) && Keypad.isColumnPressed(3))
  58. {
  59. A = 0;
  60. B = 0;
  61. C = 0;
  62. D = 1; // press D
  63. }
  64. else
  65. {
  66. /* Turn off all of LEDs. */
  67. digitalWrite(yellow,LOW);
  68. digitalWrite(green,LOW);
  69. digitalWrite(white,LOW);
  70. digitalWrite(red,LOW);
  71. }
  72. if(A) //press button A
  73. digitalWrite(yellow, HIGH);
  74. if(B) //press button B
  75. digitalWrite(green, HIGH);
  76. if(C) //press button C
  77. digitalWrite(white, HIGH);
  78. if(D) //press button D
  79. digitalWrite(red, HIGH);
  80. }
Explanation
According to the connection, upload program to the board and download the keypad app in the Playstore, install, and see the result. In the LEDs, when you press the 1 key, it is switched ON. Similarly, the other LEDs also get turned ON and OFF by the keypad app, without Bluetooth.
Output
image