I’ve done a couple of homemade dual lever paddles but recently I wanted to demonstrate my Tiny85 Arduino based keyer project at a local Maker Faire, so wanted something I could put in my pocket. In a few minutes, I made this. It’s a standard 3.5mm (1/8 inch) stereo plug. You can’t get any more portable than that.
Unscrewing the plastic shell reveals the secret sauce.
This is the dash paddle side. Just a tiny bit of thin copper soldered to the plug terminal. For those readers needing details, the copper came from the band around a Basil Hayden’s whiskey bottle. We recycle!
Here is the dot side.
A bottom view, you can see the two copper strips and how the sleeve (ground) contact was bent to form the common contact. A little careful tweaking left a thick sheet of paper’s worth of space between each copper strip and the common contact.
And the top side.
I was surprised to find it actually works. Could be useful on a QRP mountain top expedition. Have a look at this YouTube video.