ADD: functions to handle impedance packet for ganglion over wifi

Author: AJ Keller

changelog.md

@@ -1,10 +1,16 @@
-# 0.2.2
+# v0.2.3
+
+### New Features
+
+* Add function for parsing an impedance object `.parsePacketImpedance()`
+
+# v0.2.2
 
 ### Bug Fixes
 
 * Fix wrap around bug in extractRawBLEDataPackets
 
-# 0.2.1
+# v0.2.1
 
 ### Bug Fixes
 
@@ -14,47 +20,47 @@
 
 * Add features for `openbci-ganglion`
 
-# 0.2.0
+# v0.2.0
 
 ### New Feature
 
 * With scale option false, `.parsePacketStandardAccel()` `.parsePacketTimeSyncedAccel()` will now return array called will now return `accelDataCounts` property with un-scaled data.
 
-# 0.1.5
+# v0.1.5
 
 ### Bug Fixes
 
 * Was missing errors in constants used by ganglion and other ble projects.
 * Fixed getChannelData functions to support 2 channel cytons
 
-# 0.1.4
+# v0.1.4
 
 ### Bug Fixes
 
 * E-patch on new function added 0.1.3
 
 
-# 0.1.3
+# v0.1.3
 
 ### New Features
 
 * A bunch of functions to support synchronization of channel settings with cyton. Will be used by both the Wifi and the Cyton node modules.
 
-# 0.1.2
+# v0.1.2
 
 ### Bug Fixes
 
 * Send counts did not work for daisy.
 * Sample output was inconsistent
 * Fixed `timeStamp` to `timestamp` this was pr #147 (thanks @alexdevmotion)
 
-# 0.1.1
+# v0.1.1
 
 ### Bug Fixes
 
 * Send counts did not work for daisy.
 
-# 0.1.0
+# v0.1.0
 
 ### New Functions
 
@@ -64,26 +70,26 @@
 
 * Removed function called `findV2Firmware()` because it's useless with v3.0.0 firmware
 
-# 0.0.10
+# v0.0.10
 
 ### New Function
 
 * Add `boardTypeForNumberOfChannels()` to Constants
 
-# 0.0.9
+# v0.0.9
 
 ### New Features
 
 * Add impedance calculation functions from cyton
 * The simulator from OpenBCI_NodeJS has been ripped out and place into this library! Woo.
 
-# 0.0.8
+# v0.0.8
 
 ### New Features
 
 * Sample object now has property `valid` of type `boolean`, `false` when error parseing packet, `true` otherwise. On `false` there will be another property called `error` of type `string` which contains an error message.
 
-# 0.0.7
+# v0.0.7
 
 ### Continuous Integration
 
@@ -98,7 +104,7 @@
 * In openBCIUtilities.js add function `transformRawDataPacketToSample` to parse a single raw data packet
 * In openBCIConstants.js add function `rawDataToSampleObjectDefault(numChannels)` which should be used by drivers to create the object that is passed through each call to `transformRawDataPacketsToSample` 
 
-# 0.0.6
+# v0.0.6
 
 ### Bug Fixes
 
@@ -114,19 +120,19 @@
 
 * `getChannelDataArray` now takes object as only arg.
 
-# 0.0.5
+# v0.0.5
 
 ### Bug Fixes
 
 * When not scaling outputs `channelDataCounts` instead of `channelData`
 
-# 0.0.4
+# v0.0.4
 
 ### Bug Fixes
 
 * Fix bug where samples were not properly being extracted
 
-# 0.0.2
+# v0.0.2
 
 ### Breaking Changes
 
@@ -138,6 +144,6 @@
 
 * Added a function in the sample module that parses a raw buffer of OpenBCI data, extracts raw data packets and returns the buffer with just the raw data packets removed. Allowing the user to process other data that is not a raw data.
 
-# 0.0.1
+# v0.0.1
 
 Initial release

openBCIConstants.js

@@ -357,6 +357,7 @@ const obciStreamPacketAccelTimeSyncSet = 3; // 0011
 const obciStreamPacketAccelTimeSynced = 4; // 0100
 const obciStreamPacketRawAuxTimeSyncSet = 5; // 0101
 const obciStreamPacketRawAuxTimeSynced = 6; // 0110
+const obciStreamPacketImpedance = 7; // 0111
 
 /** Time from board */
 const obciStreamPacketTimeByteSize = 4;
@@ -1068,6 +1069,7 @@ const constantsModule = {
   OBCIStreamPacketAccelTimeSynced: obciStreamPacketAccelTimeSynced,
   OBCIStreamPacketRawAuxTimeSyncSet: obciStreamPacketRawAuxTimeSyncSet,
   OBCIStreamPacketRawAuxTimeSynced: obciStreamPacketRawAuxTimeSynced,
+  OBCIStreamPacketImpedance: obciStreamPacketImpedance,
   /** fun funcs */
   isNumber,
   isBoolean,

openBCIUtilities.js

@@ -28,6 +28,12 @@ let utilitiesModule = {
    * @property {Number} sampleNumber The sample number
    * @property {Array} channelData The extracted channel data
    * @property {Buffer} rawDataPacket The raw data packet
+   * @property {Boolean} valid If the sample is valid
+   */
+  /**
+   * @typedef {Object} Impedance
+   * @property {Number} channelNumber The channel number
+   * @property {Number} impedanceValue The impedance in ohms
    */
   /**
    * @typedef {Object} RawDataToSample
@@ -151,6 +157,7 @@ let utilitiesModule = {
   parsePacketStandardRawAux,
   parsePacketTimeSyncedAccel,
   parsePacketTimeSyncedRawAux,
+  parsePacketImpedance,
   /**
   * @description Mainly used by the simulator to convert a randomly generated sample into a std OpenBCI V3 Packet
   * @param sample - A sample object
@@ -569,6 +576,9 @@ let utilitiesModule = {
   samplePacketRawAuxTimeSynced: sampleNumber => {
     return new Buffer([0xA0, sampleNumberNormalize(sampleNumber), 0, 0, 1, 0, 0, 2, 0, 0, 3, 0, 0, 4, 0, 0, 5, 0, 0, 6, 0, 0, 7, 0, 0, 8, 0x00, 0x01, 0, 0, 0, 1, makeTailByteFromPacketType(k.OBCIStreamPacketRawAuxTimeSynced)]);
   },
+  samplePacketImpedance: channelNumber => {
+    return new Buffer([0xA0, channelNumber, 54, 52, 49, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, makeTailByteFromPacketType(k.OBCIStreamPacketImpedance)]);
+  },
   samplePacketUserDefined: () => {
     return new Buffer([0xA0, 0x00, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, makeTailByteFromPacketType(k.OBCIStreamPacketUserDefinedType)]);
   },
@@ -990,7 +1000,7 @@ function transformRawDataPacketsToSample (o) {
     samples.push(sample);
     if (sample.hasOwnProperty('sampleNumber')) {
       o['lastSampleNumber'] = sample.sampleNumber;
-    } else {
+    } else if (!sample.hasOwnProperty('impedanceValue')){
       o['lastSampleNumber'] = o.rawDataPacket[k.OBCIPacketPositionSampleNumber];
     }
   }
@@ -1022,6 +1032,9 @@ function transformRawDataPacketToSample (o) {
       case k.OBCIStreamPacketRawAuxTimeSynced:
         sample = utilitiesModule.parsePacketTimeSyncedRawAux(o);
         break;
+      case k.OBCIStreamPacketImpedance:
+        sample = utilitiesModule.parsePacketImpedance(o);
+        break;
       default:
         // Don't do anything if the packet is not defined
         sample = {
@@ -1290,6 +1303,31 @@ function parsePacketTimeSyncedRawAux (o) {
   return sampleObject;
 }
 
+/**
+ * @description Raw aux
+ * @param o {Object} - The input object
+ * @param o.rawDataPacket {Buffer} - The 33byte raw time synced accel packet
+ * @returns {Impedance} - An impedance object.
+ */
+function parsePacketImpedance (o) {
+  // Ths packet has 'A0','00'....,'AA','AA','FF','FF','FF','FF','C4'
+  //  where the 'AA's form an accel 16bit num and 'FF's form a 32 bit time in ms
+  // Check to make sure data is not null.
+  if (k.isUndefined(o) || k.isUndefined(o.rawDataPacket) || k.isNull(o.rawDataPacket)) throw new Error(k.OBCIErrorUndefinedOrNullInput);
+  // Check to make sure the buffer is the right size.
+  if (o.rawDataPacket.byteLength !== k.OBCIPacketSize) throw new Error(k.OBCIErrorInvalidByteLength);
+
+  let impedanceObject = {};
+
+  impedanceObject.channelNumber = o.rawDataPacket[1];
+  if (impedanceObject.channelNumber === 5) {
+    impedanceObject.channelNumber = 0;
+  }
+  impedanceObject.impedanceValue = Number(o.rawDataPacket.toString().match(/\d+/)[0]);
+
+  return impedanceObject;
+}
+
 /**
  * Use reg ex to parse a `str` register query for a boolean `offset` from index. Throws errors
  * @param str {String} - The string to search

package.json

@@ -1,6 +1,6 @@
 {
   "name": "openbci-utilities",
-  "version": "0.2.2",
+  "version": "0.2.3",
   "description": "The official utility package of Node.js SDK for the OpenBCI Biosensor Boards.",
   "main": "index.js",
   "scripts": {

test/openBCIConstants-test.js

@@ -626,6 +626,9 @@ describe('OpenBCIConstants', function () {
     it('Time Synced with Raw Aux', function () {
       assert.equal(6, k.OBCIStreamPacketRawAuxTimeSynced);
     });
+    it('Time Synced with Raw Aux', function () {
+      assert.equal(7, k.OBCIStreamPacketImpedance);
+    });
   });
   describe('Time synced with accel packet', function () {
     it('X axis', function () {

test/openBCIUtilities-test.js

@@ -1028,6 +1028,51 @@ describe('openBCIUtilities', function () {
       });
     });
   });
+  describe('#parsePacketImpedace', function () {
+    it('should extract the impedance value for channel 1', function () {
+      const expectedChannelNumber = 1;
+      const expectedImpedance = 641;
+      const rawDataPacket = openBCIUtilities.samplePacketImpedance(expectedChannelNumber);
+      let impedanceObject = openBCIUtilities.parsePacketImpedance({
+        rawDataPacket
+      });
+      expect(impedanceObject.channelNumber).to.equal(expectedChannelNumber);
+      expect(impedanceObject.impedanceValue).to.equal(expectedImpedance);
+    });
+    it('should extract the impedance value for channel 4', function () {
+      const expectedChannelNumber = 4;
+      const expectedImpedance = 64180;
+      const rawDataPacket = openBCIUtilities.samplePacketImpedance(expectedChannelNumber);
+      rawDataPacket[5] = 56;
+      rawDataPacket[6] = 48;
+      let impedanceObject = openBCIUtilities.parsePacketImpedance({
+        rawDataPacket
+      });
+      expect(impedanceObject.channelNumber).to.equal(expectedChannelNumber);
+      expect(impedanceObject.impedanceValue).to.equal(expectedImpedance);
+    });
+    it('should extract the impedance value for channel reference', function () {
+      const expectedChannelNumber = 5;
+      const expectedImpedance = 641;
+      const rawDataPacket = openBCIUtilities.samplePacketImpedance(expectedChannelNumber);
+      let impedanceObject = openBCIUtilities.parsePacketImpedance({
+        rawDataPacket
+      });
+      expect(impedanceObject.channelNumber).to.equal(0);
+      expect(impedanceObject.impedanceValue).to.equal(expectedImpedance);
+    });
+    describe('#errorConditions', function () {
+      it('send non data buffer', function () {
+        expect(openBCIUtilities.parsePacketImpedance.bind(openBCIUtilities, {
+        })).to.throw(k.OBCIErrorUndefinedOrNullInput);
+      });
+      it('wrong number of bytes', function () {
+        expect(openBCIUtilities.parsePacketImpedance.bind(openBCIUtilities, {
+          rawDataPacket: new Buffer(5)
+        })).to.throw(k.OBCIErrorInvalidByteLength);
+      });
+    });
+  });
   describe('#getDataArrayAccel', function () {
     it('compute scaled accel values', function () {
       const accelData = openBCIUtilities.getDataArrayAccel(sampleBuf.slice(k.OBCIPacketPositionStartAux, k.OBCIPacketPositionStopAux + 1));
@@ -2837,20 +2882,22 @@ describe('#transformRawDataPacketsToSamples', function () {
  * Test the function that routes raw packets for processing
  */
 describe('#transformRawDataPacketToSample', function () {
-  var funcSpyTimeSyncedAccel, funcSpyTimeSyncedRawAux, funcSpyStandardRawAux, funcSpyStandardAccel;
+  var funcSpyTimeSyncedAccel, funcSpyTimeSyncedRawAux, funcSpyStandardRawAux, funcSpyStandardAccel, funcSpyImpedance;
 
   before(function () {
     // Put watchers on all functions
     funcSpyStandardAccel = sinon.spy(openBCIUtilities, 'parsePacketStandardAccel');
     funcSpyStandardRawAux = sinon.spy(openBCIUtilities, 'parsePacketStandardRawAux');
     funcSpyTimeSyncedAccel = sinon.spy(openBCIUtilities, 'parsePacketTimeSyncedAccel');
     funcSpyTimeSyncedRawAux = sinon.spy(openBCIUtilities, 'parsePacketTimeSyncedRawAux');
+    funcSpyImpedance = sinon.spy(openBCIUtilities, 'parsePacketImpedance');
   });
   beforeEach(function () {
     funcSpyStandardAccel.reset();
     funcSpyStandardRawAux.reset();
     funcSpyTimeSyncedAccel.reset();
     funcSpyTimeSyncedRawAux.reset();
+    funcSpyImpedance.reset();
   });
   after(function () {
     // ourBoard = null
@@ -2895,6 +2942,7 @@ describe('#transformRawDataPacketToSample', function () {
     expect(funcSpyStandardRawAux).to.not.have.been.called();
     expect(funcSpyTimeSyncedAccel).to.not.have.been.called();
     expect(funcSpyTimeSyncedRawAux).to.not.have.been.called();
+    expect(funcSpyImpedance).to.not.have.been.called();
   });
   it('should throw err when no channel settings', function () {
     var buffer = new Buffer(5).fill(0);
@@ -2965,6 +3013,18 @@ describe('#transformRawDataPacketToSample', function () {
     // Ensure that we extracted only one buffer
     expect(funcSpyTimeSyncedRawAux).to.have.been.calledOnce();
   });
+  it('should process an impedance packet', function () {
+    var buffer = openBCIUtilities.samplePacketImpedance(1);
+
+    // Call the function under test
+    openBCIUtilities.transformRawDataPacketToSample({
+      channelSettings: defaultChannelSettingsArray,
+      rawDataPacket: buffer
+    });
+
+    // Ensure that we extracted only one buffer
+    expect(funcSpyImpedance).to.have.been.calledOnce();
+  });
   it('should not identify any packet', function () {
     var buffer = openBCIUtilities.samplePacket(0);
 
@@ -2982,5 +3042,6 @@ describe('#transformRawDataPacketToSample', function () {
     expect(funcSpyStandardRawAux).to.not.have.been.called();
     expect(funcSpyTimeSyncedAccel).to.not.have.been.called();
     expect(funcSpyTimeSyncedRawAux).to.not.have.been.called();
+    expect(funcSpyImpedance).to.not.have.been.called();
   });
 });