Added AccelerometerActivity

app/src/main/java/com/example/greenwatch/AccelerometerActivity.java

+package com.example.greenwatch;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.os.Bundle;
+import android.view.View;
+import android.widget.Button;
+
+public class AccelerometerActivity extends AppCompatActivity {
+
+    private Button backToMainActivityButton;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_accelerometer);
+
+        backToMainActivityButton = (Button) findViewById(R.id.accelerometerBackToMainActivity);
+
+        backToMainActivityButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                finish();
+            }
+        });
+    }
+
+}

app/src/main/res/layout/activity_accelerometer.xml

+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="10dp"
+    tools:context=".AccelerometerActivity">
+
+    <TextView
+        android:id="@+id/tvAccelerometerStatusmessage"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Accelerometer Activity">
+    </TextView>
+
+    <Button
+        android:id="@+id/accelerometerBackToMainActivity"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Back to MainActivity">
+    </Button>
+
+</LinearLayout>