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node-red/nodes/hardware/35-rpi-gpio-in.js
2013-09-05 15:02:48 +01:00

72 lines
2.2 KiB
JavaScript

/**
* 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 gpio = require("pi-gpio");
function GPIOInNode(n) {
RED.nodes.createNode(this,n);
this.buttonState = -1;
this.pin = n.pin;
this.resistor = n.resistor;
var node = this;
if (this.pin) {
var setupPin = function(err) {
if (err) {
node.error(err);
} else {
node._interval = setInterval(function(){
gpio.read(node.pin, function(err, value) {
if(err){
node.error(err);
} else{
if(node.buttonState !== value){
var previousState = node.buttonState;
node.buttonState = value;
if (previousState !== -1) {
var msg = {payload:node.buttonState};
node.send(msg);
}
}
}
});
}, 50);
}
};
if (this.resistor == "no") {
gpio.open(this.pin,"input",setupPin());
} else {
// Assume enabled externally via gpio-admin
setupPin();
}
} else {
this.error("Invalid GPIO pin: "+this.pin);
}
}
RED.nodes.registerType("rpi-gpio in",GPIOInNode);
GPIOInNode.prototype.close = function() {
clearInterval(this._interval);
if (this.resistor == "no") {
gpio.close(this.pin);
}
}