diff --git a/src/demoreader.cpp b/src/demoreader.cpp
new file mode 100644
--- /dev/null
+++ b/src/demoreader.cpp
@@ -0,0 +1,82 @@
+/*
+  Copyright © 2016 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "demoreader.h"
+
+DemoReader::DemoReader(QIODevice* device, ChannelManager* channelMan, QObject *parent) :
+    AbstractReader(device, channelMan, parent)
+{
+    paused = false;
+    _numOfChannels = 1;
+    count = 0;
+    timer.setInterval(100);
+    QObject::connect(&timer, &QTimer::timeout,
+                     this, &DemoReader::demoTimerTimeout);
+}
+
+QWidget* DemoReader::settingsWidget()
+{
+    return NULL;
+}
+
+void DemoReader::enable(bool enabled)
+{
+    if (enabled)
+    {
+        timer.start();
+    }
+    else
+    {
+        timer.stop();
+    }
+}
+
+unsigned DemoReader::numOfChannels()
+{
+    return _numOfChannels;
+}
+
+void DemoReader::setNumOfChannels(unsigned value)
+{
+    _numOfChannels = value;
+}
+
+void DemoReader::pause(bool enabled)
+{
+    paused = enabled;
+}
+
+void DemoReader::demoTimerTimeout()
+{
+    const double period = 100;
+    count++;
+    if (count >= 100) count = 0;
+
+    if (!paused)
+    {
+        for (unsigned ci = 0; ci < _numOfChannels; ci++)
+        {
+            // we are calculating the fourier components of square wave
+            double value = 4*sin(2*M_PI*double((ci+1)*count)/period)/((2*(ci+1))*M_PI);
+            _channelMan->addChannelData(ci, &value, 1);
+            sampleCount++;
+        }
+        emit dataAdded();
+    }
+}