In case you happen to have a Griffin Technologies PowerMate, which I consider to be the all-time most clever and elegantly-designed external device for Macs (and which they have been selling for a very many years), note that it can run AppleScripts. And therefore KM Macros, since those are easy to call from AppleScript, e.g.:
tell application "Keyboard Maestro Engine" to do script "Macro Name"
(See Scripting Keyboard Maestro for further details.)