Tesla Bot is a "Geiger counter for magnetic fields", and plays synthesized Geiger counter-style clicks relative to the strength of a magnetic field, as measured by the built-in compass/magnetometer of your device. This synthesis model is accurate and scales well, providing authentic Geiger counter-like clicks (modeled after the CDV-700).
*** ATTENTION! *** Please note current iPod Touch models do not have a compass (magnetometer). Tesla Bot will not function on an iPod Touch.
The approximate range in microtesla your device's magnetometer can sense is 30-2000.
Tesla Bot has several operating modes, such as detecting changes in magnetic vector (delta uT), compass degrees with heavy clicking at north, and selectable individual vector axis.
To clarify some things:
1. A magnetometer will not detect electromagnetic radiation (ie radio waves)
2. It will not detect ionizing radiation or particles ("radioactivity")
3. It mainly detects magnets and ferromagnetic materials. Note most steel alloys are austenitic (300- series) and are not ferromagnetic due to the allotropic gamma-phase shift at the curie point. (ie, they got too hot)