I know NOTHING about electronics like this. However, I am taking on a small project. I have a question that you can probably answer in half a second. I bought a few HE sensors, which are on their way. I need to know what activation sensitivity this HE sensor has in Gauss. http://www.digikey.com/product-search/en?mpart=A1302KUA-T&vendor=620 It gives me mV/G. I will be supplying it 5V from USB. I will be using this calculator to determine the size magnet I need. The furthest the magnet and HE will be is 1.8-2 inches apart. http://www.kjmagnetics.com/fieldcalculator.asp I appreciate your help. I am hoping I don't need to purchase different HE's for this build.