Introduction: 1x4 Membrane Keypad W/ Arduino

To some configuring this component may come easy, but for me- being new to tinkering with electronics, I found myself confused when trying to tinkering with this specific product. This was partly due to the fact that I couldn't find any information on how to utilize this component via Google, Arduino forums, etc. So I figure that other people might not get it, just as I did..

Product: https://www.adafruit.com/product/1332

Please keep in mind that this is my first instructable.

Step 1: BOM

Arduino (I used an UNO, but other variations would suffice)

1x4 Keypad w/ 5 Pins

5 Jumper Wires

Resistor & LED (if you prefer a visual)

Step 2: Assembly

Insert the 1x4 Keypad Header Pins into your breadboard & place 1 jumper cable directly in front of each pin of the header.

(left to right)

The first wire should be connected to a GRND Pin on your Arduino.

The 2nd, 3rd, 4th, and 5th wire should be connected to 4 Digital Pins on your Arduino. To keep it simple, I chose pins 9-12

  • Digital Pin #9, would be the #1 key on your keypad
  • Digital Pin #10, would be the #2 key on your keypad
  • Digital Pin #11, would be the #3 key on your keypad
  • Digital Pin #12, would be the #4 key on your keypad.

Verify your connections.

Step 3: Code

Paste the following into an empty Arduino Sketch & Save it. Continue to Next Step for explanations.

/*
1x4 Keypad from Adafruit.com (Unofficial Source) 
Original Source: Button
Referenced Tutorial on Arduino.com: http://arduino.cc/en/Tutorial/InputPullupSerial
Referenced: http://arduino.cc/en/Reference/pinMode
Turns on and off specified Pin or Prints to Serial Monitor when keys are press on a 1x4 keypad from Adafruit.com
The (OLD) circuit:
* LED attached from pin 13 to ground
* pushbutton attached to pin 2 from +5V
* pushbutton attached to pin 3 from +5V
* 10K resistor attached to pin 2 from ground
The (NEW) circuit (2014):
* Whichever component you want attached to Pin 13 (e.g- LED)
* 1x4 Keypad w/ primary pin attached to Ground and 1-4 keys attached to PINS 9-12
* Serial Monitor used for output (for testing, when not using anything attached to Pin 13) 
* Note: 
 
 
created 2005
by DojoDave 
modified 30 Aug 2011
by Tom Igoe
modified 10 Apr 2012
by mpilchfamily
modified 8 Dec 2014 
by C Cunningham
*
/ constants won't change. They're used here to
// set pin numbers:
const int buttonPin[] = {9,10,11,12};     // the number of the pushbutton pins
const int ledPin =  13;      // the number of the LED pin
// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status
void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);  
  // initialize the Serial Monitor @ 9600
  Serial.begin(9600);  
  // initialize the keypad pin(s) as an input:
  for(int x=0; x<2; x++)
  {
    pinMode(buttonPin[x], INPUT_PULLUP); 
  }  
}
void loop(){
  // read the state of the keypad value:
  for(int x=0; x<2; x++)
  {
    //signifying the state of which the button is in by reading the appropriate pin #
    buttonState = digitalRead(buttonPin[x]);
    // check if the pushbutton on the keypad is pressed.
    // if it is, the buttonState is LOW:
    if (buttonState == LOW && buttonPin[x] == 9) {    
      // turn LED off:   
      Serial.print("OFF * ");
      // digitalWrite(ledPin, LOW); 
    }
    if (buttonState == LOW && buttonPin[x] == 10) {
      // turn LED off:
      Serial.print("ON *");
      //digitalWrite(ledPin, LOW);
    }
  }
}

Step 4: You're Done!

Verify & Compile, Upload, and Open your Serial Monitor. Press your buttons. I only used buttons 1 & 2 for ON/OFF Functions. Code could be expanded upon to do other cool things with..