More than two years ago I posted a project to this site detailing how I took a little DDS unit I found I eBay and controlled it with an Arduino UNO and LCD. The result was a very simple and stable VFO that just about anyone could build. It was also dirt cheap to replicate. I posted the code, put up some horrible schematics, and let it sit. I never thought much of it.

Little did I know that so many people would be interested in what I had created. I’ve been contacted by a lot of people, sent a lot of pictures of users units, helped a few people trouble shoot some issues, and even got published in a few books. What I do get the most is questions. A lot of questions. So to fix repeating myself a lot on emails here are some of the most popular email questions I get about the AD7C DDS VFO.

Q: Does it work?
A: Sure does. 200+ people have contacted me thanking me after they build the same project.

Q: I get an error on compiling. Something about “rotary.h not found?”
A: You did not import the rotary library correctly.

Q: Do I have to pay you if I build this?
A: No, but you can always donate to via PayPal if you wish. I’ll be extremely thankful!

Q: I wish it had THIS feature or THAT feature. Can you add that to the code and send it to me?
A: I could but what would be the fun in that? Learning coding is part of the fun so open up the Arduino code and give it a try yourself.

Q: Can I use any rotary encoder or does it have to be the same model you used?
A: So long as the rotary encoder outputs gray code you should be OK but I can’t guarantee that.

Hopefully that helps quickly answers some questions. I am working on a new version of the code. Nothing special but I am cleaning up a few sections. I don’t like that I have two versions of the code (IF and NON-IF version) so I am combining them into one and allowing a simple code change decide which way the user would like it to function. That and a few other improvements. I’ll post when I am done. Don’t worry… it will be 100% compatible with the existing schematic so no changes there.

Go melt some solder.