Merge pull request #62 from pushtheworldllc/dev-sim-accel

Add accel data to simulator closes #61

Author: teonbrooks

changelog.md

@@ -1,3 +1,9 @@
+# 0.3.6
+
+### New Features
+
+* Simulator now has accelerometer data
+
 # 0.3.5
 
 ### New Features

openBCISample.js

@@ -296,6 +296,10 @@ var sampleModule = {
         sinePhaseRad.fill(0);
 
         var auxData = [0,0,0];
+        var accelCounter = 0;
+        // With 250Hz, every 10 samples, with 125Hz, every 5...
+        var samplesPerAccelRate = Math.floor(sampleRateHz / 25); // best to make this an integer
+        if (samplesPerAccelRate < 1) samplesPerAccelRate = 1;
 
         // Init arrays to hold coefficients for each channel and init to 0
         //  This gives the 1/f filter memory on each iteration
@@ -352,7 +356,31 @@ var sampleModule = {
             } else {
                 newSample.sampleNumber = previousSampleNumber + 1;
             }
-            newSample.auxData = auxData;
+
+            /**
+             * Sample rate of accelerometer is 25Hz... when the accelCounter hits the relative sample rate of the accel
+             *  we will output a new accel value. The approach will be to consider that Z should be about 1 and X and Y
+             *  should be somewhere around 0.
+             */
+            if (accelCounter == samplesPerAccelRate) {
+                // Initialize a new array
+                var accelArray = [0,0,0];
+                // Calculate X
+                accelArray[0] = (Math.random() * 0.1 * (Math.random() > 0.5 ? -1 : 1));
+                // Calculate Y
+                accelArray[1] = (Math.random() * 0.1 * (Math.random() > 0.5 ? -1 : 1));
+                // Calculate Z, this is around 1
+                accelArray[2] = 1 - ((Math.random() * 0.4) * (Math.random() > 0.5 ? -1 : 1));
+                // Store the newly calculated value
+                newSample.auxData = accelArray;
+                // Reset the counter
+                accelCounter = 0;
+            } else {
+                // Increment counter
+                accelCounter++;
+                // Store the default value
+                newSample.auxData = auxData;
+            }
 
             return newSample;
         };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "openbci-sdk",
-  "version": "0.3.5",
+  "version": "0.3.6",
   "description": "The official Node.js SDK for the OpenBCI Biosensor Board.",
   "main": "openBCIBoard",
   "scripts": {

test/OpenBCISample-test.js

@@ -242,6 +242,23 @@ describe('openBCISample',function() {
                 });
             });
         });
+        it('should generate a sample with accel data every 25Hz',function() {
+            var generateSample = openBCISample.randomSample(k.OBCINumberOfChannelsDefault, k.OBCISampleRate250);
+            var newSample = generateSample(0);
+
+            var passed = false;
+            // Should get one non-zero auxData array (on the 10th sample)
+            for (var i = 0; i < 10; i++) {
+                newSample = generateSample(newSample.sampleNumber);
+                if (newSample.auxData[0] !== 0 || newSample.auxData[1] !== 0 || newSample.auxData[2] !== 0) {
+                    passed = true;
+                    newSample.auxData[0].should.be.approximately(0,0.1);
+                    newSample.auxData[1].should.be.approximately(0,0.1);
+                    newSample.auxData[2].should.be.approximately(1,0.4);
+                }
+            }
+            assert(passed,"a sample with accel data was produced");
+        });
     });
     describe('#impedanceCalculationForChannel', function() {