stumbled across someone using their mobile with an app to test their turntables speed...

before hit the app store was wondering if anyone has done it, what they thought of the results and have any app recommendations...

Freeware shoud good enough. Best way is with a strobe on the platter or side (like the Techies markings on the side of the platter) then with phone in hand and light on strobe. That way one should get preciser measurments and even 'Wow' and 'Flutter' ratios. Other ways might be fair (like phone on platter) for a ball park idea but no more really. As for programms I can't say. They will work differently in regard of how it will measure the platter resolutions. What is more important I've understood is the quality of the "smart" or 'I' phone inner components...

I truly can't say more as I only use my ears for that. Those infos I've read on phono audio forums.