73-bmp085.js

/**
 * Copyright 2015 Sergey Krasnov <me@sergeykrasnov.ru>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/
 
// BMP085 Node-RED node file
module.exports = function(RED) {
	var BMP085 = require('bmp085');

// Set the bmp085 debug option from the environment variable
	var debugOption = false;
	if (process.env.hasOwnProperty("RED_DEBUG") && process.env.RED_DEBUG.indexOf("bmp085") >= 0) {
		debugOption = true;
	}

    function bmp085_Node(config) {
        RED.nodes.createNode(this,config);

        // node configuration
		this.device = config.device;
		this.timer = config.timer * 1000;
		this.name = config.name;
		this.pressureUnits = config.pressureUnits || "mmHg";
		this.temperatureUnits = config.temperatureUnits || "degC";
		if (this.pressureUnits === "hPa" || this.pressureUnits === "mBar") {
			this.pressureFactor = 1.0;
		} else if (this.pressureUnits === "mmHg") {
			this.pressureFactor = 0.75006;
		} else if (this.pressureUnits === "inHg") {
			this.pressureFactor = 0.0295299;
		} else {
			this.pressureFactor = 1.0;
		}
		this.seaLevel = config.seaLevel || "QFE";
		// Note: height units are only used in the editor: config.height is always in m
		this.height = config.height || 0;
		this.heightUnits = config.heightUnits || "m";
		var node = this;
		
		var sensor = new BMP085({
				'mode': 2,
				'address': '0x77',
				'device': this.device,
				'debug' : debugOption
		});
		
		var getData = function(){
			// TODO: error handling
			sensor.read(function (data) {
				// data.pressure = (data.pressure/1.3332239).toFixed();
				if (node.seaLevel === "QNH") {
					data.pressure *= Math.pow(288.15/(288.15-0.0065*node.height), 5.255876);
				}
				data.pressure *= node.pressureFactor;
				data.pressure = Math.round(data.pressure);
				if (node.temperatureUnits === "degF") {
					data.temperature = 32 + data.temperature*1.8;
				}
				var msg = { payload: data };
				node.send(msg);
			});	
		}
		
		getData(); // run on start
		
		tID = setInterval(getData, this.timer);
		node.on("close", function() {
			clearInterval(tID);
		});
    }

    // Register the node by name.
    RED.nodes.registerType("bmp085",bmp085_Node);
}