Visualizing Johnny-Five Arduino PWM on Web Oscilloscope

In the world of electronics, diagnosing problems with electronic circuits can be a daunting task. The ability to view and analyze the signals produced by electronic components is an important aspect of troubleshooting. One such signal is the Pulse Width Modulation (PWM) signal, which is commonly used in electronic circuits to control the output of devices such as motors, LEDs, and speakers. In this article, we will explore how to use Johnny-Five and Arduino to produce a PWM signal and how to visualize it using a free online web oscilloscope.

What is Johnny-Five?

Johnny-Five is a JavaScript framework that allows you to control electronic components using the JavaScript programming language. It provides an easy-to-use API that abstracts the low-level details of working with microcontrollers such as Arduino. With Johnny-Five, you can write code to control a wide range of electronic components, including sensors, LEDs, motors, and more. One of the features of Johnny-Five is the ability to produce a PWM signal, which we will explore in more detail. If you want to learn the basics see LED blink with Johnny-Five and Arduino.

Producing a PWM Signal with Johnny-Five and Arduino

To produce a PWM signal using Johnny-Five and Arduino, we will use the previous beginner guide to PWM with Johnny-Five and Arduino tutorial. The circuit diagram and Johnny-Five Javascript program code is available in that tutorial. Here we will only show how to view the PWM signal generated by the Arduino using Johnny-Five Javascript library on free web oscilloscope so that you can visualize the PWM signal waveform and check that it is as expected.

Visualizing the PWM Signal using a Web Oscilloscope

Once you have produced a PWM signal using Johnny-Five and Arduino, we can then visualize it using a web oscilloscope. A web oscilloscope is a free online oscilloscope tool that allows you to view and analyze electronic signals in real-time using a web browser. To use the online web browser oscilloscope open the following link:

Then connect the output PWM signal from Arduino to the Line-in input of your PC/Laptop  or mobile phone. Then click on the ON/OFF button to start the oscilloscope. You should see the PWM waveform on the oscilloscope. You can then change the duty cycle of the PWM signal by rotating the potentiometer knob and see the PWM signal waveform changes on the oscilloscope. To analye the signal you can use the amplitude slider and time slider to change the amplitude and time range for the signal.Hovering over the signal gives the time and amplitude information which you can record to calculate frequency, noise and other information. You can zoom in and out, and take a screenshot of the signal waveform. 

 visualizing signal on web oscilloscope

The following video demonstrates how to visualize Johnny-Five and Arduino produced PWM signal on the web oscilloscope.

Using a web oscilloscope can be incredibly useful for diagnosing problems with electronic circuits. It allows you to quickly and easily visualize the signals produced by your circuit and make adjustments as necessary.


In this article, we explored how to use Johnny-Five and Arduino to produce a PWM signal and how to visualize it using a free web oscilloscope. We first discussed what Johnny-Five is and how to use it to produce a PWM signal. We then introduced the Siglent Oscilloscope app and demonstrated how to use it to visualize the PWM signal produced by our Arduino board.This web oscilloscope not only can be used to analyze PWM signal but also analyze signal of electronics circuit such as op amp oscillator circuit, lm358 amplifier circuit , active bandpass filter circuit, self Biased BJT amplifier etc. The web oscilloscope is also useful to view live sensor data. Using a web oscilloscope can be a valuable tool for diagnosing problems with electronic circuits, and we encourage you to give it a try!

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