node-red/nodes/core/hardware/36-rpi-gpio.js

/**
 * Copyright 2013 IBM Corp.
 *
 * 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.
 **/

module.exports = function(RED) {
    var util = require("util");
    var exec = require('child_process').exec;
    var fs =  require('fs');
    
    if (!fs.existsSync("/dev/ttyAMA0")) { // unlikely if not on a Pi
        throw "Info : Ignoring Raspberry Pi specific node.";
    }
    
    if (!fs.existsSync("/usr/local/bin/gpio")) { // gpio command not installed
        throw "Info : Can't find Raspberry Pi wiringPi gpio command.";
    }
    
    // Map physical P1 pins to Gordon's Wiring-Pi Pins (as they should be V1/V2 tolerant)
    var pintable = {
    // Physical : WiringPi
            "11":"0",
            "12":"1",
            "13":"2",
            "15":"3",
            "16":"4",
            "18":"5",
            "22":"6",
             "7":"7",
             "3":"8",
             "5":"9",
            "24":"10",
            "26":"11",
            "19":"12",
            "21":"13",
            "23":"14",
             "8":"15",
            "10":"16"
    }
    var tablepin = {
    // WiringPi : Physical
            "0":"11",
            "1":"12",
            "2":"13",
            "3":"15",
            "4":"16",
            "5":"18",
            "6":"22",
            "7":"7",
            "8":"3",
            "9":"5",
           "10":"24",
           "11":"26",
           "12":"19",
           "13":"21",
           "14":"23",
           "15":"8",
           "16":"10"
    }
    
    function GPIOInNode(n) {
        RED.nodes.createNode(this,n);
        this.buttonState = -1;
        this.pin = pintable[n.pin];
        this.intype = n.intype;
        var node = this;
    
        if (this.pin) {
            exec("gpio mode "+node.pin+" "+node.intype, function(err,stdout,stderr) {
                if (err) node.error(err);
                else {
                    node._interval = setInterval( function() {
                        exec("gpio read "+node.pin, function(err,stdout,stderr) {
                            if (err) node.error(err);
                            else {
                                if (node.buttonState !== Number(stdout)) {
                                    var previousState = node.buttonState;
                                    node.buttonState = Number(stdout);
                                    if (previousState !== -1) {
                                        var msg = {topic:"pi/"+tablepin[node.pin], payload:node.buttonState};
                                        node.send(msg);
                                    }
                                }
                            }
                        });
                    }, 250);
                }
            });
        }
        else {
            this.error("Invalid GPIO pin: "+this.pin);
        }
    
        this.on("close", function() {
            clearInterval(this._interval);
        });
    }
    
    function GPIOOutNode(n) {
        RED.nodes.createNode(this,n);
        this.pin = pintable[n.pin];
        var node = this;
    
        if (this.pin) {
            process.nextTick(function() {
                exec("gpio mode "+node.pin+" out", function(err,stdout,stderr) {
                    if (err) node.error(err);
                    else {
                        node.on("input", function(msg) {
                            if (msg.payload === "true") msg.payload = true;
                            if (msg.payload === "false") msg.payload = false;
                            var out = Number(msg.payload);
                            if ((out == 0)|(out == 1)) {
                                exec("gpio write "+node.pin+" "+out, function(err,stdout,stderr) {
                                    if (err) node.error(err);
                                });
                            }
                            else node.warn("Invalid input - not 0 or 1");
                        });
                    }
                });
            });
        }
        else {
            this.error("Invalid GPIO pin: "+this.pin);
        }
    
        this.on("close", function() {
            exec("gpio mode "+this.pin+" in");
        });
    }
    
    exec("gpio mode 0 in",function(err,stdout,stderr) {
        if (err) {
            util.log('[36-rpi-gpio.js] Error: "gpio" command failed for some reason.');
        }
        exec("gpio mode 1 in");
        exec("gpio mode 2 in");
        exec("gpio mode 3 in");
        exec("gpio mode 4 in");
        exec("gpio mode 5 in");
        exec("gpio mode 6 in");
        exec("gpio mode 7 in");
    });
    
    RED.nodes.registerType("rpi-gpio in",GPIOInNode);
    RED.nodes.registerType("rpi-gpio out",GPIOOutNode);
}