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node-red-nodes/hardware/mcp3008/pimcp3008.js
2016-09-20 08:19:45 +01:00

77 lines
2.6 KiB
JavaScript

/**
* Copyright 2016 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 fs = require('fs');
// unlikely if not on a Pi
try { fs.statSync("/dev/ttyAMA0"); }
catch(err) { throw "Info : Ignoring Raspberry Pi specific node"; }
var mcpadc = require('mcp-spi-adc');
var mcp3008 = [];
function PiMcpNode(n) {
RED.nodes.createNode(this,n);
this.pin = n.pin || 0;
this.interval = n.interval || 1000;
var node = this;
try {
fs.statSync("/dev/spidev0.0");
if (mcp3008.length === 0) {
for (var i=0; i<8; i++) {
mcp3008.push(mcpadc.open(i, function (err) {
if (err) { node.error("Error: "+err); }
}));
}
}
node.on("input", function(msg) {
var pin = null;
if (node.pin === "M") {
var pay = parseInt(msg.payload.toString());
if ((pay >= 0) && (pay <= 7)) { pin = pay; }
else { node.warn("Payload needs to select channel 0 to 7"); }
}
else { pin = parseInt(node.pin); }
if (pin !== null) {
mcp3008[pin].read(function (err, reading) {
if (err) { node.warn("Read error: "+err); }
else { node.send({payload:reading.rawValue, topic:"adc/"+pin}); }
});
}
});
}
catch(err) {
node.error("Error : Can't find SPI device - is SPI enabled in raspi-config ?");
}
node.on("close", function(done) {
if (mcp3008.length !== 0) {
var j=0;
for (var i=0; i<8; i++) {
mcp3008[i].close(function() { j += 1; if (j === 8) {done()} });
}
mcp3008 = [];
}
else { done(); }
});
}
RED.nodes.registerType("pimcp3008",PiMcpNode);
}