3.Controlling a Servo Motor with a Keypad and Arduino

Controlling a Servo Motor with a Keypad and Arduino

Components Needed:

1. Arduino board
2. 4x4 or 4x3 Keypad
3. Servo motor
4. Jumper wires
5. Breadboard (optional)

Connections:

1. Keypad: Connect the keypad pins to digital pins on your Arduino (e.g., rows to pins 9, 8, 7, 6 and columns to pins 5, 4, 3, 2).
2. Servo: Connect the servo motor:
• Signal pin to a PWM digital pin on the Arduino (e.g., pin 10).
• Power (VCC) to 5V.
• Ground (GND) to GND.

Example Code:

C++ Code

#include <Keypad.h>
#include <Servo.h>

const byte ROWS = 4; // Number of rows
const byte COLS = 4; // Number of columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {9, 8, 7, 6};    // Connect to row pins of keypad
byte colPins[COLS] = {5, 4, 3, 2};     // Connect to column pins of keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

Servo myServo; // Create a Servo object

int servoPin = 10; // Connect servo signal pin to pin 3
int angle = 0;    // Servo position (0 to 180 degrees)

void setup() {
  myServo.attach(servoPin); // Attach the servo to the pin
  myServo.write(angle);     // Set initial servo position to 0 degrees
  Serial.begin(9600);
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    Serial.println(key);

    // Control servo based on key press
    switch (key) {
      case '1':
        angle = 0;  // Set servo to 0 degrees
        break;
      case '2':
        angle = 90; // Set servo to 90 degrees
        break;
      case '3':
        angle = 180; // Set servo to 180 degrees
        break;
      case '4':
        angle += 10; // Increment servo angle by 10 degrees
        if (angle > 180) angle = 180; // Limit to 180 degrees
        break;
      case '5':
        angle -= 10; // Decrement servo angle by 10 degrees
        if (angle < 0) angle = 0; // Limit to 0 degrees
        break;
      default:
        break;
    }

    myServo.write(angle); // Move servo to the specified angle
  }
}

Explanation:

1. Libraries Import: The Keypad and Servo libraries are included for keypad and servo control.
2. Define Rows and Columns: Set the number of rows and columns of the keypad.
3. Key Mapping and Pin Assignments: Assign the keypad pins and map the keys.
4. Servo Setup: Define the servo pin, create a Servo object, and attach it to the pin.
5. Loop Logic:
   • Use keypad.getKey() to detect key presses.
   • Depending on the key pressed:
     • Keys '1', '2', and '3' set the servo to 0, 90, and 180 degrees, respectively.
     • Keys '4' and '5' adjust the servo angle incrementally by 10 degrees.

Tips:

• Make sure to use an external power supply if your servo motor requires more current than the Arduino can provide.
• You can modify the keys to control the servo in different ways, such as using other keys for more precision or adding more preset positions.