A Useless Machine with delay and howl

The useless machine or ultimate machine originates from Claude Shannon, the scientist who figured out how to find the channel capacity in a communications system. I bought the basic machine as a kit from Solarbotics.

But then I added a few features:

  • A delay circuit that makes it look more alive as it gives the impression of doing some thinking before it responds to the switch.
  • Sound that varies with how open the lid is and the amount of light that hits the photosensitive resistor. It was inspired by the design of the Growl and Scream Altoids of FightCube.
  • A couple of LEDs, a red one when it opens and a blue one when it closes.

The circuits were built on small pieces of veroboard and the circuit diagram can be downloaded from here. In retrospect I’m not completely happy with the sound, it could have growled and screamed even more, but then how much effort can one really justify putting into a project which is – useless – anyway?

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at [email protected].

Leave a Comment

Subscribe FREE to AmateurRadio.com's
Amateur Radio Newsletter
News, Opinion, Giveaways & More!

Join over 7,000 subscribers!
We never share your e-mail address.

Also available via RSS feed, Twitter, and Facebook.

Subscribe FREE to AmateurRadio.com's
Amateur Radio Newsletter

We never share your e-mail address.

Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on AmateurRadio.com!

Have a ham radio product or service?
Consider advertising on our site.

Are you a reporter covering ham radio?
Find ham radio experts for your story.

How to Set Up a Ham Radio Blog
Get started in less than 15 minutes!

  • Matt W1MST, Managing Editor

Sign up for our free
Amateur Radio Newsletter

Enter your e-mail address: