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

/**
 * Copyright 2013,2014 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) {
    "use strict";
    var util = require("util");
    var exec = require('child_process').exec;
    var fs =  require('fs');

    var gpioCommand = '/usr/local/bin/gpio';

    if (!fs.existsSync("/dev/ttyAMA0")) { // unlikely if not on a Pi
        throw "Info : Ignoring Raspberry Pi specific node.";
    }

    if (!fs.existsSync(gpioCommand)) { // 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",
            "27":"30",
            "28":"31",
            "29":"21",
            "31":"22",
            "32":"26",
            "33":"23",
            "35":"24",
            "36":"27",
            "37":"25",
            "38":"28",
            "40":"29"
    }
    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",
           "30":"27",
           "31":"28",
           "21":"29",
           "22":"31",
           "26":"32",
           "23":"33",
           "24":"35",
           "27":"36",
           "25":"37",
           "28":"38",
           "29":"40"
    }

    function GPIOInNode(n) {
        RED.nodes.createNode(this,n);
        this.buttonState = -1;
        this.pin = pintable[n.pin];
        this.intype = n.intype;
        this.read = n.read || false;
        if (this.read) { this.buttonState = -2; }
        var node = this;

        if (node.pin !== undefined) {
            exec(gpioCommand+" mode "+node.pin+" "+node.intype, function(err,stdout,stderr) {
                if (err) { node.error(err); }
                else {
                    node._interval = setInterval( function() {
                        exec(gpioCommand+" 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 {
            node.error("Invalid GPIO pin: "+node.pin);
        }

        node.on("close", function() {
            clearInterval(node._interval);
        });
    }

    function GPIOOutNode(n) {
        RED.nodes.createNode(this,n);
        this.pin = pintable[n.pin];
        this.set = n.set || false;
        this.level = n.level || 0;
        this.out = n.out || "out";
        var node = this;
        (node.out === "pwm") ? (node.op = "pwm") : (node.op = "write");

        if (node.pin !== undefined) {
            exec(gpioCommand+" mode "+node.pin+" "+node.out, function(err,stdout,stderr) {
                if (err) { node.error(err); }
                else {
                    if (node.set && (node.out === "out")) {
                        exec(gpioCommand+" write "+node.pin+" "+node.level, function(err,stdout,stderr) {
                            if (err) { node.error(err); }
                        });
                    }
                    node.on("input", function(msg) {
                        if (msg.payload === "true") { msg.payload = true; }
                        if (msg.payload === "false") { msg.payload = false; }
                        var out = Number(msg.payload);
                        var limit = 1;
                        if (node.out === "pwm") { limit = 1023; }
                        if ((out >= 0) && (out <= limit)) {
                            exec(gpioCommand+" "+node.op+" "+node.pin+" "+out, function(err,stdout,stderr) {
                                if (err) { node.error(err); }
                            });
                        }
                        else { node.warn("Invalid input: "+out); }
                    });
                }
            });
        }
        else {
            node.error("Invalid GPIO pin: "+node.pin);
        }

        node.on("close", function() {
            exec(gpioCommand+" mode "+node.pin+" in");
        });
    }

    var pitype = { type:"" };
    exec(gpioCommand+" -v | grep Type", function(err,stdout,stderr) {
        if (err) {
            util.log('[36-rpi-gpio.js] Error: "'+gpioCommand+' -v" command failed for some reason.');
        }
        else {
            pitype = { type:(stdout.split(","))[0].split(": ")[1], rev:(stdout.split(","))[1].split(": ")[1] };
        }
    });

    RED.nodes.registerType("rpi-gpio in",GPIOInNode);
    RED.nodes.registerType("rpi-gpio out",GPIOOutNode);

    RED.httpAdmin.get('/rpi-gpio/:id',function(req,res) {
        res.send( JSON.stringify(pitype) );
    });
}