Tried this a while ago with an electric lawnmower, having used a scarifier on golf courses for years. My effort was crap although it did work, but a bit too much needed to make it viable and my lack of workshop facilities or time resulted in it going nowhere
I think it needs the right speed, the right length of straps, decent enclosure and ideally vacuumed, I'd have thought it would be better to have the straps attached to a "spindle " rather than the beater bar.
Good that someones having a go at this and could lead to customising machines