Monthly Archives: October 2012

Arduino PWM in slow motion

Although I’m mostly working with the “normal” digital input / output on the Arduino, it might be a good idea to play with the PWM output, too, just to have a basic knowledge about it if needed.

I’ll not go too much into detail about the theoretical background of PWM (highly suggesting you to read the Wikipedia article about PWM if you want to learn more about it). Simply speaking, PWM on the Arduino creates an analogue signal between 0 and 5 Volts by pulsing the power with an interval, e.g. to provide 50% (2.5 Volts) the power is pulsed at a rate of 500 Hz (Arduino uses this frequency for PWM) with half of the time provding either 5 Volts or 0 Volts.

So, what about connecting a LED to the Arduino PWM, powering it at 50% and using high speed video recording?

Arduino PWM in slow motion from Nils on Vimeo.

At 1000 frames per second you can see the flickering that is caused by the switching power on and off at high frequency.

I currently don’t have any use case for PWM in my projects but it’s good to know how it basically works if needed ;)

New open source project: jspinfo

Just some shameless self-promotion:

I recently uploaded my 3rd open-source project to It’s called jspinfo() and – for all of you who are familiar with PHP – it’s like phpinfo() but as a JSP file.

So, if you are a developer and you need some information about some common server settings, then give jspinfo() a try: just upload the file to your Java-based application server (preferrable Apache Tomcat) and open it in your browser.

For more information and the download please visit

If you have any comments, ideas or other feedback on jspinfo() please visit the jspinfo() Ticket system or the discussion forum.