I am the creator and product manager for this product at WeatherFlow. Previous founder of CAMRIG (sold privately - no longer own).
In a very candid manor... The initial design of our product was geared toward the US market and US phones, some units leaked into the EU market and were not functional on those devices due to volume restrictions (power output on the headphone jack). The EU limits how loud your speakers go... We have since updated to a new circuit (literally changed one resister in the electrical engineering). The updated circuit is still battery free but fully compatible with the EU phones. If for some reason you live in EU and are having trouble we will replace your unit free of charge no questions asked (with the exception of some basic debugging to ensure there really is a problem). All units now ship with this circuit, from all 7 of our warehouses and from every point of distribution.
Lastly, we are working on a NIST certification for our quality control standard. Although we are incredibly strict out of the factory right now we are taking it to a totally different level by installing a wind tunnel in our factory http://www.nist.gov/calibrations/air_speed_instruments.cfm
this is our highest priority at this time.
Our competitors have a really long way to come, especially on the scientific side. I wont bother mentioning names but a few mentioned in this thread averaged a steady 20% off and some contained major major aerodynamic design flaws. My goal isn't really to "push" this item on forums as much as I am interested in feedback, etc... our banner on forums is the offset / advertisement
Here is a list of devices we have tested end to end...iOS Compatibility:
iOS 7.x, iOS 6.x, iOS 5.x
iPhone 5 / iPhone 5s
iPhone 4S / iPhone 4
iPad (Gen 1 - 4)
iPod Touch (Gen 3 - 5)Android Compatibility:
Android 2.3, 3.2, 4
Samsung Galaxy S2
Samsung Galaxy S3
Samsung Galaxy S4
HTC Evo 4G
HTC Evo 4G LTE
Droid Razr, HD, M
Droid Maxx & Ultra XT1080
Just because you do not see your phone listed here does not mean our wind meter wont work.
Thanks for your help everyone