Implements PIR sensor inferface; calibrated, motionstart, motionend e…

…vents

Signed-off-by: Rick Waldron waldron.rick@gmail.com <waldron.rick@gmail.com>

examples/pir.js

@@ -0,0 +1,51 @@
+var arduino = require('../'),
+    board, pir;
+
+board = new arduino.Board({
+  debug: false
+});
+
+pir = new arduino.PIR({
+  board: board,
+  pin: 7
+});
+
+// 'calibrated' event fired when PIR sensor is
+// ready to detect movement/motion in observable range
+//
+// All events receive error and date arguments
+pir.on('calibrated', function(err, date) {
+
+  console.log('calibrated');
+
+  // Current sensor data stored in properties
+  // of this PIR instance:
+  //
+  // this.state - current state of motion
+  //     0 No motion currently detected
+  //     1 Motion currently detected
+
+  // 'motionstart' event fired when motion occurs
+  // within the observable range of the PIR sensor
+  this.on('motionstart', function(err, date) {
+
+    console.log('motionstart', this.state);
+    console.log( date );
+
+  });
+
+  // 'motionend' event fired when motion has ceased
+  // within the observable range of the PIR sensor
+  this.on('motionend', function(err, date) {
+
+    console.log('motionend', this.state);
+
+  });
+});
+
+
+// To test, use the following:
+// http://www.ladyada.net/images/sensors/pirardbb.gif
+//
+// More information:
+// http://www.ladyada.net/learn/sensors/pir.html

index.js

@@ -6,5 +6,6 @@ module.exports = {
   Button: require('./lib/button'),
   Servo:  require('./lib/servo'),
   Sensor: require('./lib/sensor'),
-  Ping:   require('./lib/ping')
+  Ping:   require('./lib/ping'),
+  PIR:    require('./lib/pir')
 };

lib/pir.js

@@ -0,0 +1,69 @@
+var events = require('events'),
+    util = require('util');
+
+/*
+ * Main PIR constructor
+ * Process options
+ * Tell the board to set it up
+ */
+var PIR = function (options) {
+  if (!options || !options.board) {
+    throw new Error('Must supply required options to PIR');
+  }
+  this.board = options.board;
+  this.pin = this.board.normalizePin(options.pin || 9);
+  this.state = null;
+  this.calibrated = false;
+
+  setInterval(function () {
+    this.board.digitalRead(this.pin);
+  }.bind(this), 50);
+
+  this.board.on('data', function (message) {
+    var m = message.slice(0, -1).split('::'),
+        timestamp = new Date(),
+        err = null,
+        pin, data;
+
+    if (!m.length) {
+      return;
+    }
+
+    pin = m[0];
+    data = m[1];
+
+    if (pin === this.pin) {
+
+      // If this is not a calibration event
+      if (this.state != null && this.state != +data) {
+
+        // Update current state of PIR instance
+        this.state = +data;
+
+        // 'motionstart' event fired when motion occurs
+        // within the observable range of the PIR sensor
+        if (data === '01') {
+          this.emit('motionstart', err, timestamp);
+        }
+
+        // 'motionend' event fired when motion has ceased
+        // within the observable range of the PIR sensor
+        if (data === '00') {
+          this.emit('motionend', err, timestamp);
+        }
+      }
+
+      // 'calibrated' event fired when PIR sensor is
+      // ready to detect movement/motion in observable range
+      if (!this.calibrated) {
+        this.calibrated = true;
+        this.state = +data;
+        this.emit('calibrated', err, timestamp);
+      }
+    }
+  }.bind(this));
+};
+
+util.inherits(PIR, events.EventEmitter);
+
+module.exports = PIR;