8x8matrix/8x8matrix.js

A simple node.js-based helper for the Raspberry Pi and the Adafruit 8x8 Matrix

const rpio = require('rpio');

var Matrix = function(data) {

	if (typeof data == 'undefined') data = {}

	this.brightness = data.brightness || 15;
	this.write_buffer = [];
	this.current_array = [];

	rpio.i2cBegin();
	rpio.i2cSetSlaveAddress(data.slaveAddress || 0x70);
	rpio.i2cSetBaudRate(data.bautrate || 10000);

	// Turn on the oscillator
	rpio.i2cWrite(Buffer([(0x20 | 0x01)]));

	// Turn display on
	rpio.i2cWrite(Buffer([(0x01 | 0x80)]));

	// Initial Clear
	for (var x = 0; x < 16; x++) {
		rpio.i2cWrite(Buffer([x, 0]));
	}

	// Set display to full brightness.
	rpio.i2cWrite(Buffer([(0xE0 | this.brightness)]));
}

Matrix.prototype.setBrightness = function(b) {

	if (b > 15) b = 15;
	if (b < 0) b = 0;

	rpio.i2cWrite(Buffer([(0xE0 | b)]));
}

Matrix.prototype.setLED = function(y, x, value) {
	var led = y * 16 + ((x + 7) % 8);

	var pos = Math.floor(led / 8);
	var offset = led % 8;


	if (value)
		this.write_buffer[pos] |= (1 << offset);
	else
		this.write_buffer[pos] &= ~(1 << offset);
}

Matrix.prototype.writeArray = function(_array) {
	this.current_array = _array;
	this.clearBuffer();

	var x = 0;
	var y = 0;

	for (var i in _array) {
		this.setLED(y, x, _array[i]);

		x++;

		if (x >= 8) {
			y++;
			x = 0;
		}

	}

	this.writeBuffer();
}

Matrix.prototype.writeAnimation = function(_array, speed) {
	var self = this;
	var old_buffer = this.write_buffer.slice();

	for (var i in _array) {
		self.writeAnimation2(i, _array[i], speed);
	}

	setTimeout(function() {

		self.clearBuffer();
		self.writeBuffer();

	}, _array.length * speed + speed);

	setTimeout(function() {

		self.write_buffer = old_buffer.slice();
		self.writeBuffer();

	}, _array.length * speed + 1000);
}

Matrix.prototype.writeAnimation2 = function(i, data, speed) {
	var self = this;

	setTimeout(function() {
		self.writeArray(data);
	}, speed * i);
}

Matrix.prototype.writeBuffer = function() {
	for (var i in this.write_buffer) {
		rpio.i2cWrite(Buffer([i, this.write_buffer[i]]));
	}
}

Matrix.prototype.clearBuffer = function() {
	for (var i in this.write_buffer) {
		this.write_buffer[i] = 0;
	}
}

Matrix.prototype.smily = [
	0,0,1,1,1,1,0,0,
	0,1,0,0,0,0,1,0,
	1,0,1,0,0,1,0,1,
	1,0,0,0,0,0,0,1,
	1,0,1,0,0,1,0,1,
	1,0,0,1,1,0,0,1,
	0,1,0,0,0,0,1,0,
	0,0,1,1,1,1,0,0,
];

module.exports = Matrix;