Membrane Keypad

I have decided to build a smart thermostat for the Shop's mini-split AC and a smart controller for the lawn sprinkler controller (also in the shop).   After using the Dust Collector's Data Terminal (it works great) for several years, I decided I needed another DT for other projects.   It had occurred to me that I could slightly reduce the complexity (and $) if I used a membrane keypad.   It would be much less expensive and I wouldn't need a special cable.   I had already decided to add it to the RS-485 net in the shop which would slightly complicate the DT.