eTesla

By using data from the phone internal compass, This app can measure the magnetic field generated from metals Or high electromagnetic emission from High Voltage line ,Transformer , Electric motors,and some home appliance such as microwave oven. The units of measure is Tesla -µT : Nikola Tesla (10-Jul-1856 - 07-Jan-1943) inventor of the Tesla coil and developer of inductor motor working by alternate current. The normal earth emissions is around 20-40 µT. High magnetic field can reach 200 µT (e.g. near to speakers). In very high magnetic field (e.g. near electric motors ) it can be over 300 µT such high magnetic field ,can easy damage credit ,mechanical watch . If the phone has been exposed to e high magnetic field , the sensor need to be recalibrate by just shake the phone until the data reader become normal range. A alarm can be set by the slider, over that value the value become red and the phone will vibrate. So: stay away from strong magnetic field : find it and avoid it.