An R-2R resistor ladder is a nice little method of doing digital to analog conversion.
The one I made is 8-bit, so it can output 256 different voltages from 0V to 3.3V. Here are some pics:

You can see on my oscilloscope that I'm generating a saw wave. All I'm doing is counting from 0 to 255 really fast over and over again, and putting the number onto the 8 pins of the PIC that are connected to the resistor ladder. You can also see on the oscilloscope that the wave isn't perfectly straight, and that's because of the resistors' tolerance that is differing the resistance slightly. There's nothing I can do to fix that, except use resistors with smaller tolerance.

Here's a close up pic of the ladder:

If you want to learn more about this take a look at the wikipedia page here.
Nice job! What oscilloscope is that? I'm glad to see you're messing around with some electronics development, and learning how D-A conversion actually works, at least on a crude level, is superb.
Kerm: The oscilloscope is a Velleman Instruments HPS-10.

I'm also thinking of making sound with this. The only things I'd need to put on the outside of this would be a transistor and a speaker, and I could be making some 8-bit music Very Happy
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.

» Go to Registration page
Page 1 of 1
» All times are UTC - 5 Hours
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum