accel-mma84 - npm Package Compare versions

Comparing version 0.0.3 to 0.0.4

examples/accelerometer.js

@@ -1,4 +0,7 @@
-// var hardware = require('hardware');
+/*********************************************
+This basic accelerometer example logs a stream
+of x, y, and z data from the accelerometer
+*********************************************/
+
 var tessel = require('tessel');
-console.log("Connecting to acceleroemter on port bank A");
 var accel = require('../').connect(tessel.port("A"));
@@ -8,10 +11,8 @@
 accel.on('connected', function () {
-  // Loop forever.
-  setInterval(function () {
-    accel.getAcceleration(function (err, xyz) {
-      console.log("x:", xyz[0].toFixed(2),
-        "y:", xyz[1].toFixed(2),
-        "z:", xyz[2].toFixed(2));
-    });
-  }, 100);
+	// Stream accelerometer data
+	accel.on('data', function (xyz) {
+		console.log("x:", xyz[0].toFixed(2),
+      "y:", xyz[1].toFixed(2),
+      "z:", xyz[2].toFixed(2));
+	});
 });

examples/average.js

@@ -1,4 +0,7 @@
-// This example is a more colorful accelerometer example.
+/*********************************************
+This is a more colorful accelerometer example.
+*********************************************/
 
-var mma8452q = require('accel-mma84');
+var tessel = require('tessel');
+var accel = require('../').connect(tessel.port("A"));
 
@@ -33,12 +36,14 @@ function pad (f) {
 
-mma8452q.initialize();
+// Initialize the accelerometer.
+accel.on('connected', function () {
+  // Stream accelerometer data
+  accel.on('data', function (xyz) {
+    var avgs = [];
+    for (var i = 0; i < 5; i++) {
+      avgs.push(xyz);
+    }
 
-while (1) {
-  var avgs = [];
-  for (var i = 0; i < 5; i++) {
-    avgs.push(mma8452q.getAcceleration());
-  }
-
-  var x = avg(avgs, 0), y = avg(avgs, 1), z = avg(avgs, 2);
-  console.log("x:", red(pad(x)), "  y:", green(pad(y)), "  z:", yellow(pad(z)));
-}
+    var x = avg(avgs, 0), y = avg(avgs, 1), z = avg(avgs, 2);
+    console.log("x:", red(pad(x)), "  y:", green(pad(y)), "  z:", yellow(pad(z)));
+  });
+});

index.js

@@ -33,6 +33,8 @@ var util = require('util');
 
-  this.hardware = hardware;
+  self.hardware = hardware;
+  self.numListeners = 0;
+  self.listening = false;
+  self.pollFrequency = 100;
 
   self.i2c = new hardware.I2C(I2C_ADDRESS);
-  self.i2c.initialize();
 
@@ -60,3 +62,35 @@ self._readRegister(WHO_AM_I, function (err, c) {
     });
-  })
+    // If we get a new listener
+    self.on('newListener', function(event) {
+      if (event == "data") {
+        // Add to the number of things listening
+        self.numListeners += 1;
+        // If we're not already listening
+        if (!self.listening) {
+          // Start listening
+          self.setListening();
+        }
+      }
+    });
+
+    // If we remove a listener
+    self.on('removeListener', function(event) {
+      if (event == "data") {
+        // Remove from the number of things listening
+        console.log('prev listeners', self.numListeners);
+        self.numListeners -= 1;
+        console.log('now', self.numListeners);
+        // Because we listen in a while loop, if this.listening goes to 0, we'll stop listening automatically
+        if (self.numListeners < 1) {
+          self.listening = 0;
+        }
+      }
+    });
+
+    // If all listeners removed
+    self.on('removeAllListeners', function(event) {
+      self.numListeners = 0;
+      self.listening = 0;
+    });
+  });
 }
@@ -84,2 +118,18 @@
 
+Accelerometer.prototype.setListening = function () {
+  var self = this;
+  self.listening = true;
+  // Loop until nothing is listening
+  self.listeningLoop = setInterval (function () {
+    if (self.numListeners) {
+      self.getAcceleration(function (err, xyz) {
+        if (err) throw err;
+        self.emit('data', xyz);
+      });
+    } else {
+      clearInterval(listeningLoop);
+    }
+  }, self.pollFrequency);
+}
+
 // Sets the MMA8452 to standby mode. It must be in standby to change most register settings
@@ -109,2 +159,3 @@ Accelerometer.prototype.modeStandby = function (next)
   self._readRegisters(OUT_X_MSB, 6, function (err, rawData) {
+    if (err) throw err;
     // Loop to calculate 12-bit ADC and g value for each axis
@@ -129,2 +180,12 @@ var out = [];
 
+// Sets the polling frequency for streamed data (default 100ms)
+Accelerometer.prototype.setPollFrequency = function (milliseconds) {
+  var self = this;
+  self.pollFrequency = milliseconds;
+  if (self.listening) {
+    clearInterval(self.listeningLoop);
+    self.setListening();
+  }
+}
+
 exports.Accelerometer = Accelerometer;
@@ -131,0 +192,0 @@ exports.connect = function (hardware) {

package.json

 {
   "name": "accel-mma84",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "description": "Library to run the MMA8452Q accelerometer.",
@@ -9,2 +9,5 @@ "main": "index.js",
   },
+  "hardware": {
+    "./examples": false
+  },
   "repository": "",
@@ -11,0 +14,0 @@ "author": "Tim Cameron Ryan <[e-mail]>",

README.md

@@ -1,16 +0,30 @@
-# MMA8452Q accelerometer driver
+#Accelerometer
+Driver for the accel-mma84 Tessel accelerometer module ([MMA8452Q](http://www.freescale.com/files/sensors/doc/data_sheet/MMA8452Q.pdf)).
 
-Install:
-
-```
+##Installation
+```sh
 npm install accel-mma84
 ```
 
-Import:
+##Example
+```js
+// var hardware = require('hardware');
+var tessel = require('tessel');
+console.log("Connecting to accelerometer on port bank A");
+var accel = require('accel-mma84').connect(tessel.port("A"));
 
+// Initialize the accelerometer.
+accel.on('connected', function () {
+  // Loop forever.
+  setInterval(function () {
+    accel.getAcceleration(function (err, xyz) {
+      console.log("x:", xyz[0].toFixed(2),
+        "y:", xyz[1].toFixed(2),
+        "z:", xyz[2].toFixed(2));
+    });
+  }, 100);
+});
 ```
-var accel = require('accel-mma84').connect(myhardwareapi);
-```
 
-Functions:
+##Methods
 
@@ -21,4 +35,14 @@ *  **`accel`.initialize()**
 
+##Events
+
+* *connected*
+
+* *data*
+
+##Further Examples
+
+* [Average (more advanced use)](https://github.com/tessel/modules/blob/master/accel-mma84/examples/average.js)
+
 ## License
 
 MIT

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Improved metrics

Total package byte prevSize

9586

increased by71.21%

Number of package files

6

increased by20%

Lines of code

244

increased by64.86%

Number of lines in readme file

48

increased by100%

No dependency changes