Designing an indicator. It has been done before and there are numbers derived from market internal numbers like Advancing Volume vs Declining Volume vs Unchanged Volume or Advancing Issues vs Declining Issues vs Unchanged Issues
But nothing is better to understand an indicator, if you try to build one for yourself. Think what you want to see if certain parameters are met and then start designing with the numbers you have. See if it makes sense, if it gives you the results you look for.
I'm thinking Volume preceedes price movement. If there is no trade, there is no price movement. Of course we can have huge price swings on low volume, but the market as a whole moves on volume. And that's the reason I'm thinking about the numbers mentioned above.
Currently I have Excel open, plugged in some arbitrary numbers and am experimenting with some formulas. Keep it simple, logical (not stupid)
I will let you know, what I'm finding