Rebuilding My SDR Tuning Knob in Spotted Gum

A while back I made a Tuning Wheel For SDR Radio on my PC Using an Angle Sensor. When plugged into a PC, this behaves as a mouse wheel. I’m using it as a tuning knob for SDR software. It works well but I was never very happy with the enclosure. I guess ‘enclosure’ is not really the correct term as it was more of a mount. It was made from a few bits of pine and while it was sturdy, I wanted it to be a bit prettier, because I’m superficial like that 🙂

This is what it was like.

I wanted to try using a dark hardwood so headed off to Bunnings, a popular home hardware store here in Australia. I found a stack of 1.5m long spotted gum fence pickets for about $7.00 each. I had not intended to look at fence pickets, but the timber did look decent. I hunted through and found one of the better looking ones that had good colour and not too warped.

I believe these have been seasoned and oiled, but this could still turn out to be a disaster. We have spotted gum flooring in our kitchen and while it looks good, there has been a small amount of warping over the years. I hope that using a small piece it may not be so bad.

The timber is 20 mm thick. Originally, I planned to glue two pieces together to double the thickness and then hollow out space for the electronics, but I quickly abandoned that idea.

I drilled a 25mm hole most of the way through the centre of one piece to house the sensor and magnet assembly. I had intended to connect a permanent USB cable to the ESP32-S3 Super Mini. I went looking for the data connections and found they were not broken out on this module. They are only available through the USB socket, so I gave up on that idea.

I cut two pieces of timber at an angle and glued these to the ends. I didn’t worry too much about aligning them at the ends. When the glue had dried I recut the ends to give it a smooth cut finish. I cut a bit more off one side than the other and now the hole was no longer right in the centre, but it’s not too far off. I went around the edges with a router to round it all off.

The AS5600 magnetic sensor is held in place with hot melt glue and a piece of old PCB.

Paint and clear coats can easily be the most expensive part of simple projects, so I went hunting through what I had. There was a small amount in the bottom of a can of polyurethane. It was a bit jellied, but I went ahead and got a rag and rubbed it into the timber. It looked great. It still looked great a week later, but it was still sticky. Hmmm… out with the turps and off with that coat. I found a can of satin polyurethane and tried that. Two days later it was still sticky so out with the turps again.

I had a can of furniture wax and decided to try it. It was easy to apply and gave a surprisingly pleasant feel and appearance.

So that’s it. It was a fairly simple update. Even though I made a few mistakes I am happier with this version and it gave me the chance to try out this method of making a project mount with this timber. I like the timber’s pleasant colour and heavy feel and I’ve already started using it in other projects.

I use SDRconnect for my SDR radio. It doesn’t appear to have any hotkeys and I can’t find a way to make the wheel always adjust the tuning. The mouse pointer has too be over the correct part of the screen. It would be nice if I could find a way around that.