I turned the magnet over this morning. It definitely has an effect. Not quiet what I was hoping for though.:(
With it turned over the tacho didn't work at all. Just sat there displaying four Zero's.
So I changed it around again.
Its still fluctuating. Maybe its just a heap of crap. Most of the stuff I have bought from Banggood has been ok so I suppose I have to expect a dud occasionally.
Here's a 30 second video I took this morning. Motor running at a set frequency.
https://youtu.be/KUzLDjr0X5o
Peter