pidriver

Node.js bind of wiringPi lib

Installation

$ [sudo] npm install pidriver

Usage

Some functions may need root privileges

$ [sudo] node myapp

API is at most sync but any function that have callback(cb) can by async

//sync
var ret = input.write(0);

//async
input.write(0, function(err, ret){
	console.log(arguments);
})

Using "mods"

	var pi = require('pidriver');

	pi.INPUT	//'in'

	//all mods:

	var mods = {
		//Gpio mode:
		INPUT: 'in',
		OUTPUT: 'out',

		//for internal use rather (best not to use)
		PWM_OUTPUT: 2,
		GPIO_CLOCK: 3,

		//Gpio states:
		LOW: new Buffer('0'),
		HIGH: new Buffer('1'),

		// Gpio pull
		PUD_OFF: 0,
		PUD_DOWN: 1,
		PUD_UP: 2,

		// PWM
		PWM_MODE_MS: 0,
		PWM_MODE_BAL: 1,

		// Interrupt levels
		INT_EDGE_NONE: 'none',
		INT_EDGE_SETUP: 0,
		INT_EDGE_FALLING: 'falling',
		INT_EDGE_RISING: 'rising',
		INT_EDGE_BOTH: 'both'
	};

Gpio

var pi = require('pidriver'),
    led = new pi.Gpio('GPIO27', {mode: pi.OUTPUT}),
    input = new pi.Gpio('GPIO24', {pull: pi.PUD_UP});

input.on('up', function(input){
	console.log('Button is pressed');
	led.up();	//light up led
});

input.on('down', function(input){
	console.log('Button is unpressed');
	led.down();	//turn off led
});

new Gpio(gpio [,options])

gpio - pin number / 'GPIOx' / 'WPIOx' / 'special name'

You can use pin number or one of most popular names: 'GPIOx' for official gpio numbering, 'WPIOx' for wiringPi gpio numbering or its special name like 'PWM0' (for 12s pin) pin map

Full list of available names:

var pi = require('pidriver');

console.log(pi.pins)

/*	example for 12s pin:
	{
		...
		12: {name: ['PWM0','GPIO18', 'WPIO1'], gpio: 18, able: true, pullable: true},
		...
	}

	Pin number: 12
	Available names: PWM0, GPIO18, WPIO1
	Usable as Gpio
	Pullable (see below)
*/

options

	//default
	{
		edge: pi.INT_EDGE_BOTH,
		mode: pi.INPUT,
		pull: pi.PUD_OFF,
		state: 0	//initial state
	}

About mode and pull wiringPi doc, use "mods" for edge, mode, pull

Gpio is also Event Emitter:

Gpio.on('event', cb)

events: 'change' - state change 'up' - state 1 'down' - state 0

Gpio methods

• Gpio.read([cb]) - read state

• Gpio.write(state [,cb]) - set state

• Gpio.up([cb]) - set state high

• Gpio.down([cb]) - set state low

• Gpio.setEdge(edge)

• Gpio.setDirection(dir)

• Gpio.setPull(pud)

• Gpio.isPullable()

• Gpio.isInput()

• Gpio.isOutput()

• Gpio.direction() - get direction

• Gpio.options() - get options

• Gpio.unexport()

Group

	var pi = require('pidriver'),
	led0 = new pi.Gpio('GPIO27', {mode: _.OUTPUT}),
	led1 = new pi.Gpio('GPIO22', {mode: _.OUTPUT}),
	led2 = new pi.Gpio('GPIO22', {mode: _.OUTPUT});

	var group = new pi.Group([led0, led1, led2]);
	group.up();	//light up all leds
	group.write(5);	// turn on leds: led0 and led2

new Group(gpios)

gpios - Array of Gpio

Group methods

• Group.read([cb])

• Group.write(value [,cb])

value is number (you can use hex(0xFF) also) number is formatted to bits array (85 -> 01010101) and asian to proper pin

• Group.up([cb])

• Group.down([cb])

PWM

	var pi = require('pidriver'),
	pwm = new pi.PWM('PWM0', {});

	console.log('PWM start blinking');
	var state = 0;

	setInterval(function() {
		state += 50;

		if(state>1023)
			state = 0;

		pwm.write(state);
	}, 100);

new PWM(gpio [,options])

gpio - gpio name, see Gpio

options

//default
{
	clock: 2,
	range: 1024,
	mode: mods.PWM_MODE_BAL,
	duty: 0
}

about range, clock, mode see PWM, for mode use "mods"

PWM methods

• PWM.isHW() - is hardware PWM (only supported)

• PWM.setRange(range)

• PWM.setClock(clock)

• PWM.setMode(mode)

• PWM.write(value[, cb])

• PWM.options()

• PWM.unexport()

SPI

$ gpio load spi

	var pi = require('pidriver'),
		spi = new pi.SPI(0, {
			preBuffering: function(buff, arg){
				buff.writeUInt8(1, 0);
				buff.writeUInt8((8+arg)<<4, 1);
				buff.writeUInt8(0, 2);
				return buff;
			},
			postBuffering: function(buff, arg){
				return ((buff[1]&3)<<8) + buff[2];
			}
		});

	//post and preBuffering code from http://www.raspberrypi-spy.co.uk/2013/10/analogue-sensors-on-the-raspberry-pi-using-an-mcp3008/
	//example of reading channel 0 on MCP3008

	setInterval(function(){
		var channel = 0;
		console.log(spi.read(channel));
	},200);

new SPI(channel [,options])

channel - there is only two channels (0 and 1 (CE0 and CE1 pin))

options

	//default
	{
		channel: 0,
		clock: 1000000,
		preBuffering: null,
		postBuffering: null,
		words: 3
    }

SPI methods

• SPI.options()

• SPI.write(data, arg [,cb])

• SPI.read(arg [,cb])

• SPI.transfer(data, arg [,cb])

LCD

	var pi = require('pidriver'),
		lcd = new pi.LCD(['GPIO7','GPIO8','GPIO25','GPIO24','GPIO23','GPIO18']);

 	lcd.home();

 	var i = 0,
 		t = ['-','\\','|','/'];

	setInterval(function(){
		lcd.setPosition(0,1);
		lcd.write(new Buffer(t[++i%4]));
	} , 500)

new LCD(gpios [,options])

gpios - array of GPIO name (first is rs, second strb, channel0, channel1, ...)

options

	//default
	{
		rows: 2,	//number of LED's rows
		cols: 16,	//number of LED's cols
		bits: 4		//number of LED's channel (4 or 8 depends on LCD and installation)
	}

LCD methods

• LCD.clear([cb])

• LCD.home([cb])

• LCD.write([cb])

• LCD.setPosition(x, y [,cb])