Using phone app to monitor string tension (Part-1/2)

Before I describe my layman version of the authors technique, please assist to review the original article at Badmintoncentral - give credit where credit is due.

They provide a technical in-depth discussion of the technique and the science behind it. 

Do you know how to make use of the information presented to actually monitor the tension on your badminton racquet?

If not, tune back next month and I will reveal how the average Joe can monitor their racquet tension without any expensive tools.

FYI Grommet replacement for Yonex Z-Force 2 (and alike)

Recently had to help a client replace the "in-line" grommets at the upper half of a Yonex Z-force 2, as it seem to be cutting into the string. 

Now for the shocking news - I called the local Yonex distributor as well as various local shops and they tell me to go order the replacement from overseas myself, as they would charge a processing fee for the item.

Why is it shocking, you say? 

If you try ordering it, the "in-line" grommet is not available as a single item. You must buy the entire set of grommets for the Z-Force2 at about USD$12 per set!!! This is before cost for shipping etc.

KUDOS to Yonex for this easy money making scheme!

So owners of the Z-Force2 and some models of ArcSaber/NanoRay/Voltaric be aware of these impending future expenses.