gpio-matrix-keypad

This is a simple node package I developed after having trouble with some of the other packages available. I tested this with a 3x4 keypad and a raspberry pi. Please make sure that you row GPIO connections are either all pulldown or all pullup. If you use pullup connections you will need to set defaultState = 0 in the options.

The default pullup/pulldown GPIO connections are available in Table 6-31 in the BCM2835 ARM Peripherals documentation.

Install

npm install gpio-matrix-keypad --save

Usage

const Keypad = require('gpio-matrix-keypad');

const options = {
    keys: [
        ['1', '2', '3'],
        ['4', '5', '6'],
        ['7', '8', '9'],
        ['*', '0', '#']
    ], // keypad layout
    rows: [26, 19, 13, 21], // row GPIO pins. Use ones that pull down or are configured to pull down
    columns: [11, 9, 10], // colum GPIO pins,
    onKey: (key)=> console.log(key) //key pressed
    //defaultState: 1 // 1 for pulldown row gpio, 0 for pullup rows. The default is 1. Mixing of pullup/pulldown for the row connections is not supported.
};

Keypad.listen(options)

Example

This is an example of using this package to acquire a 4 digit pin code and doing something with it.

const Keypad = require('gpio-matrix-keypad');

let pin = [];

function newKey(key) {
    pin.push(key);

    if (pin.length === 4) submit();
}

function submit() {
    console.log(pin.join(''));
    pin = [];
}

const options = {
    keys: [
        ['1', '2', '3'],
        ['4', '5', '6'],
        ['7', '8', '9'],
        ['*', '0', '#']
    ], // keypad layout
    rows: [26, 19, 13, 21], // row GPIO pins. Use ones that pull down or are configured to pull down
    columns: [11, 9, 10], // colum GPIO pins,
    onKey: newKey
    //defaultState: 1 // 1 for pulldown row gpio, 0 for pullup rows. The default is 1. Mixing of pullup/pulldown for the row connections is not supported.
};

Keypad.listen(options)