diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index dc5507e..bad0e90 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -12,6 +12,7 @@
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
     <uses-feature
         android:name="android.hardware.bluetooth_le"
diff --git a/app/src/main/java/com/mooshim/mooshimeter/main/TrendActivity.java b/app/src/main/java/com/mooshim/mooshimeter/main/TrendActivity.java
index 2b479d7..a941795 100644
--- a/app/src/main/java/com/mooshim/mooshimeter/main/TrendActivity.java
+++ b/app/src/main/java/com/mooshim/mooshimeter/main/TrendActivity.java
@@ -44,6 +44,13 @@
 
 import java.util.Calendar;
 
+import java.io.*;
+import android.app.Activity;
+import android.os.Bundle;
+import android.view.*;
+import android.view.View.OnClickListener;
+import android.widget.*;
+
 public class TrendActivity extends Activity {
 
     private static final String TAG="TrendActivity";
@@ -336,6 +343,28 @@ public void run() {
                         public void run() {
                             addDataPoint(new_time,val[0],val[1]);
                             mGraph.forceRefresh(true, false);
+                            /** Data logging hack. */
+                            String textToSaveString = String.valueOf(new_time) + "," + String.valueOf(val[0]) + "," + String.valueOf(val[1]) +'\n';
+                            try {
+                                File myFile = new File("/sdcard/mooshimeter_data.txt");
+                                if(!myFile.exists()) {
+                                    myFile.createNewFile();
+                                }
+                                FileOutputStream fOut = new FileOutputStream(myFile,true);
+                                OutputStreamWriter myOutWriter =
+                                        new OutputStreamWriter(fOut);
+                                myOutWriter.append(textToSaveString);
+                                myOutWriter.close();
+                                fOut.close();
+                                Toast.makeText(getBaseContext(),
+                                        "Done writing SD 'mysdfile.txt'",
+                                        Toast.LENGTH_SHORT).show();
+                            } catch (Exception e) {
+                                Toast.makeText(getBaseContext(), e.getMessage(),
+                                        Toast.LENGTH_SHORT).show();
+                            }
+        
+                            final String FILENAME = "myFile.txt";                            
                         }
                     });
                 }