node-red/nodes/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.
 **/

var RED = require("../../red/red");
var util = require("util");
var exec = require('child_process').exec;
var fs =  require('fs');

if (!fs.existsSync("/usr/local/bin/gpio")) {
    exec("cat /proc/cpuinfo | grep BCM27",function(err,stdout,stderr) {
        if (stdout.indexOf('BCM27') > -1) {
            util.log('[36-rpi-gpio.js] Error: Cannot find Wiring-Pi "gpio" command. http://wiringpi.com/download-and-install/');
        }
        // else not on a Pi so don't worry anyone with needless messages.
    });
    return;
}

// Map physical P1 pins to Gordon's Wiring-Pi Pins (as they should be V1/V2 tolerant)
var pintable = {
// Physical : WiringPi
         "7":"7",
        "11":"0",
        "12":"1",
        "13":"2",
        "15":"3",
        "16":"4",
        "18":"5",
        "22":"6"
}
var tablepin = {
// WiringPi : Physical
        "7":"7",
        "0":"11",
        "1":"12",
        "2":"13",
        "3":"15",
        "4":"16",
        "5":"18",
        "6":"22"
}

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);
    }
}

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);
    }
}

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",function(err,stdout,stderr) {
        RED.nodes.registerType("rpi-gpio in",GPIOInNode);
        RED.nodes.registerType("rpi-gpio out",GPIOOutNode);

        GPIOInNode.prototype.close = function() {
            clearInterval(this._interval);
        }

        GPIOOutNode.prototype.close = function() {
            exec("gpio mode "+this.pin+" in");
        }

    });
});