After buying my Yaesu FT-991a and using it for Field Day, I realized that some functions are a bit annoying to control. In particular, getting the voice keyer going requires the display to show the specific recording buttons for operation. This blocks the waterfall as well as other quick settings which is not ideal. After looking online a bit, I came across a webpage from YO5PTD and GitHub project from PY2RAF giving some details on building your own version of the relatively pricey Yaseu FH-2 keypad controller (affiliate link).
My goal was to throw together my own version of this keypad without having to buy any parts, so I dug through my junk box to find parts that will work out. In the end, I used some old SPST momentary switches left over from a college microcontrollers class, a hodge-podge of resistors that got me within 10% or so of the values listed on the other pages, an old chopped audio cable, a screw terminal block, spare capacitor, some perf board, and some rubber feet and put this together.
Not much to it, but it works great! For “free,” this is going to be a helpful tool when I operate portable for contests and a QSO parties. My novel aspect is that I built this on one piece of perf board, and then sandwiched a second board under it and soldered a few jumpers through to protect the connections on the bottom. Not foolproof but saved me having to find/buy/build/drill and enclosure! Only downside is that there is not a good way to label the buttons but a small card with labels could suffice. I really only plan to use the voice memories anyway, so I only care about the first five buttons which are self explanatory based on position.
The takeaway here is that while the resistor values in the original project seem very specific and non-standard, if you have a set of common resistors, you can probably find combinations that get you close enough. Same with the capacitor; the keypad works fine without it, but I found a close value and haven’t had any problems.