Howdy folks,
There are several countdown macros on the forum already, but I didn’t see any that make use of Keyboard Maestro’s progress bar action (though I might have just missed them if there are). This one uses that action to display the countdown, updating both the text and colored bar in real-time.
More details, screenshots and screen recordings are below. As usual, feel free to share any comments or suggestions, or to let me know if it doesn’t work for you.
-Chris
47)[MG-SUBRT] Show countdown using progress bar.kmmacros (20 KB)
CURRENT VERSION: 1.0.0 (Friday, July 28, 2023)
Version History
v1.0.0 Friday, July 28, 2023
Initial macro
Screen recordings (click to expand/collapse)
↓ Starting the countdown ↓
↓ Stopping the countdown early ↓
RELEASE NOTES, INSTRUCTIONS AND DISCLAIMER
Purpose of this macro (click to expand/collapse)
Display a countdown timer using Keyboard Maestro’s progress bar action
How this macro works (click to expand/collapse)
This macro first parses the %TriggerValue% token to extract the action (start or stop countdown) and duration (in seconds).
It then performs calculations to determine how many times the progress bar must be updated according to the supplied duration.
After that it loops the progress bar, performing calculations to format the time in HH:MM:SS format and updating both the bar and text until the countdown has finished.
How to configure this macro (click to expand/collapse)
No configuration necessary.
How to use this macro (click to expand/collapse)
Run it as an execute a macro action with the parameter and asynchronously options checked.
In the parameter field, insert the word “Start” or “Stop”, followed by how many seconds you want for the countdown.
If stopping, you do not need to supply the seconds portion.
Example: Start 300 (for starting a 5 minute countdown)
Example: Stop (for stopping any countdown)
Disclaimer (click to expand/collapse)
TL;DR: I built it and it works for me. You can share/modify it how you want. But don't blame me if it doesn’t work for you 
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.