@zqasd, WATR is not a metal, it is a chemical compund that conducts electricity, due to its simplicity in nature. @Aamths, Yes, it would be more accurate to call it that XD (silicons are just metalloids).
@LiquidPlasma & @FooFoo4230, This is because the detection is dependent on NOT gate decision. Each unit is three pixels tall; NOT gates are difficult to compact at this point.
Your metal detector cannot detect things less than 3 pixels high
*condutive elements detector
Cannot detect single conductive pixels, no matter the number. Requires atleast two pixels adjacent to one another. Pretty cool though, +1.