Testing Arduino DDS signal with Online Web Oscilloscope

In one of previous article on DDS using Arduino, it was shown how to create a Direct Digital Synthesizer (DDS) with an Arduino board to generate a sine wave signal. Here, it is shown you how to test the Arduino DDS using an online web oscilloscope.

An oscilloscope is a device that allows you to visualize the waveform of an electrical signal over time. While physical oscilloscopes can be expensive and cumbersome, online web oscilloscopes offer a convenient and affordable way to test your Arduino DDS.

Step 1: Set up your Arduino DDS

Before you can test your DDS, you'll need to set it up according to the instructions in our previous tutorial on Arduino DSS. Here's a quick recap:

Shown below is picture showing Arduino DDS connected to PC line-in input socket using 3.5mm audio cable.

audio socket arduino

Below is the circuit diagram for the Arduino DDS.

Direct Digital Synthesis (DDS) Arduino animation

  • Connect the output pin 11 of the Arduino board to a low-pass filter circuit.
  • Connect the output of the low pass filter to the audio socket pin.
  • Connect 10KOhm potentiometer to the analog pin A0 for frequency control
  • Upload the DDS sketch to the Arduino board using the Arduino IDE.

Step 2: Open the Web Oscilloscope

  • Open your web browser and go to https://www.ee-diary.com/2023/04/online-real-time-signal-web-oscilloscope.html.

You should now see the Oscilloscope web app opened in your web browser.

Step 3: Connect the Oscilloscope to your Arduino DDS

  • To connect the Oscilloscope app to your Arduino DDS, connect the output of the low pass filter to the audio socket pin. to your computer's audio input.
  • Connect one end of the audio cable to the audio socket.
  • Connect the other end of the audio cable to your computer's audio input.

Note: If your computer doesn't have a separate audio input, you may need to use an audio interface or USB audio adapter.

Step 4: Configure the Oscilloscope

Now that your DDS and Oscilloscope are connected, you can configure the Oscilloscope to display the waveform of the sine wave signal. Click on the On button of the web oscilloscope app. The browser will ask for permission to connect the Line In or Microphone. Use Line in input option. Then you should be able to see the waveform generated by Arduino DDS on the web oscilloscope.

Step 5: Test the Arduino DDS

With the Oscilloscope app opened and waveform displayed, you can then test your circuit, in this case the Arduino DSS functioning. You can rotate the potentiometer connected to Arduino to adjust the frequency of the sine wave and see that higher or lower frequency on the oscilloscope. You can also adjust the time scale, adjust the amplitude using the slider or knob on the free web oscilloscope.Watch the waveform on the Oscilloscope app to see how it changes in response to the changes in the DDS output.

Shown below is picture which shows DDS signal on actual oscilloscope and on the web oscilloscope.

web oscilloscope vs real oscilloscope

Video demonstration of testing Arduino DDS signal with online web oscilloscope is below.


You are not limited to testing signal from Arduino based DDS but you can also use the free web oscilloscope to test electronics circuits like filters, op amp audio amplifier, transistor based amplifiers such as 2n3904 amplifier circuit, op-amp lm358 amplifier circuit etc.

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