thinkmorse.sh

#!/bin/bash

modprobe -r ec_sys
modprobe ec_sys write_support=1

on="\x8a"
off="\x0a"

led(){
	echo -n -e $1 | dd of="/sys/kernel/debug/ec/ec0/io" bs=1 seek=12 count=1 conv=notrunc 2> /dev/null
	# thx to u/vali20
	# https://www.reddit.com/r/thinkpad/comments/7n8eyu/thinkpad_led_control_under_gnulinux/
}

dit(){
	led $on
	sleep 0.1
	led $off
	sleep 0.1
}

dah(){
	led $on
	sleep 0.3
	led $off
	sleep 0.1
}

morse(){
	case $1 in
		"0") dah; dah; dah; dah; dah;;
		"1") dit; dah; dah; dah; dah;;
		"2") dit; dit; dah; dah; dah;;
		"3") dit; dit; dit; dah; dah;;
		"4") dit; dit; dit; dit; dah;;
		"5") dit; dit; dit; dit; dit;;
		"6") dah; dit; dit; dit; dit;;
		"7") dah; dah; dit; dit; dit;;
		"8") dah; dah; dah; dit; dit;;
		"9") dah; dah; dah; dah; dit;;
		"a") dit; dah;;
		"b") dah; dit; dit; dit;;
		"c") dah; dit; dah; dit;;
		"d") dah; dit; dit;;
		"e") dit;;
		"f") dit; dit; dah; dit;;
		"g") dah; dah; dit;;
		"h") dit; dit; dit; dit;;
		"i") dit; dit;;
		"j") dit; dah; dah; dah;;
		"k") dah; dit; dah;;
		"l") dit; dah; dit; dit;;
		"m") dah; dah;;
		"n") dah; dit;;
		"o") dah; dah; dah;;
		"p") dit; dah; dah; dit;;
		"q") dah; dah; dit; dah;;
		"r") dit; dah; dit;;
		"s") dit; dit; dit;;
		"t") dah;;
		"u") dit; dit; dah;;
		"v") dit; dit; dit; dah;;
		"w") dit; dah; dah;;
		"x") dah; dit; dit; dah;;
		"y") dah; dit; dah; dah;;
		"z") dah; dah; dit; dit;;
		" ") sleep 0.6;;
		#*) echo "done";;
	esac
	sleep 0.2;
}

parse(){
	tmp=$1
	for i in $(seq 0 ${#tmp})
	do
		echo "current letter: ${tmp:$i:1}"
		morse ${tmp:$i:1}
	done
}

led $off
read -p "enter a word: " input
echo "blinking \"$input\""
parse "$input"

sleep 1
led $on

modprobe -r ec_sys

If you are using nixos you can have your LEDs permanently blink messages using the following module:

{ pkgs, lib, config, ... }:
{
  options = {
    services.thinkmorse = {
      enable = lib.mkEnableOption "Enable morse on the thinkpad led";
      message = lib.mkOption {
        type = lib.types.str;
        default = "Hello, World!";
        description = "The message to display in morse code";
      };
      devices = lib.mkOption {
        type = lib.types.listOf lib.types.str;
        default = [ "tpacpi::lid_logo_dot" ];
        description = "The devices to use for morse code";
      };
      speed = lib.mkOption {
        type = lib.types.str;
        default = "0.1";
        description = "Duration of a dit in seconds";
      };
    };
  };
  config = lib.mkIf config.services.thinkmorse.enable (
    let
      ditDelay = config.services.thinkmorse.speed;
      thinkmorse = pkgs.writeShellScriptBin "thinkmorse" ''
        #!${pkgs.bash}/bin/bash

        modprobe -r ec_sys
        modprobe ec_sys write_support=1

        led(){
          ${lib.concatStringsSep "\n" (builtins.map (device: ''echo $1 | ${pkgs.coreutils}/bin/tee /sys/class/leds/${device}/brightness'' ) config.services.thinkmorse.devices )}
        }

        dit(){
                led 1
                sleep ${ditDelay}
                led 0
                sleep ${ditDelay}
        }

        dah(){
                led 1
                sleep ${ditDelay}
                sleep ${ditDelay}
                sleep ${ditDelay}
                led 0
                sleep ${ditDelay}
        }

        morse(){
                case $1 in
                        "0") dah; dah; dah; dah; dah;;
                        "1") dit; dah; dah; dah; dah;;
                        "2") dit; dit; dah; dah; dah;;
                        "3") dit; dit; dit; dah; dah;;
                        "4") dit; dit; dit; dit; dah;;
                        "5") dit; dit; dit; dit; dit;;
                        "6") dah; dit; dit; dit; dit;;
                        "7") dah; dah; dit; dit; dit;;
                        "8") dah; dah; dah; dit; dit;;
                        "9") dah; dah; dah; dah; dit;;
                        "a") dit; dah;;
                        "b") dah; dit; dit; dit;;
                        "c") dah; dit; dah; dit;;
                        "d") dah; dit; dit;;
                        "e") dit;;
                        "f") dit; dit; dah; dit;;
                        "g") dah; dah; dit;;
                        "h") dit; dit; dit; dit;;
                        "i") dit; dit;;
                        "j") dit; dah; dah; dah;;
                        "k") dah; dit; dah;;
                        "l") dit; dah; dit; dit;;
                        "m") dah; dah;;
                        "n") dah; dit;;
                        "o") dah; dah; dah;;
                        "p") dit; dah; dah; dit;;
                        "q") dah; dah; dit; dah;;
                        "r") dit; dah; dit;;
                        "s") dit; dit; dit;;
                        "t") dah;;
                        "u") dit; dit; dah;;
                        "v") dit; dit; dit; dah;;
                        "w") dit; dah; dah;;
                        "x") dah; dit; dit; dah;;
                        "y") dah; dit; dah; dah;;
                        "z") dah; dah; dit; dit;;
                        " ") sleep ${ditDelay}; sleep ${ditDelay}; sleep ${ditDelay}; sleep ${ditDelay}; sleep ${ditDelay}; sleep ${ditDelay} ;;
                        #*) echo "done";;
                esac
                sleep 0.2;
        }

        parse(){
                tmp=$1
                for i in $(seq 0 ''${#tmp})
                do
                        echo "current letter: ''${tmp:$i:1}"
                        morse ''${tmp:$i:1}
                done
        }
        led 0
        parse "${config.services.thinkmorse.message}"
        led 0
        sleep 1
      '';
    in
    {
      systemd.services.thinkmorse = {
        enable = true;
        description = "Morse a message on the thinkpad led";
        after = [ "systemd-modules-load.service" ];
        wantedBy = [ "multi-user.target" ];
        serviceConfig = {
          Restart = "always";
          Type = "simple";
          ExecStart = "${lib.getExe thinkmorse}";
        };
      };

    }
  );
}