I'd like to run a macro 20 seconds after the clock of the computer completes a minute, so for example, at 7:18:20 pm, then 7:19:20, then 7:20:20 pm and so on until I stop it. I've looked around for code on the web, but all I can find is something similar to this:

sub test()
Application.OnTime Now + TimeValue("00:01:00"), "my_macro"
end sub
the code above would run something every minute, I believe, but only every minute starting from the time you execute the sub named "test". What I'd like is code that specifically runs x amount of seconds after the computer clock completes a minute, no matter when I execute it. So if I execute the "test" macro above at 7:17:40 pm, I do not want it to run until 7:18:20 pm. Is this possible?

Also, since it will be on an infinite loop, can I stop it with another macro? I can just tie a button to it...

Thank you.