Hello Francisco,
Apologies for the delayed response!
Yes, detection of the pin-like objects is certainly possible, but we do not have anything specific on the topic.
General guideline is that you want to design your coil according to the shape of the objects, ie if the object is 5cm long, your coil has to be 5cm long, and as thin as possible - as long as the LDC can drive such a coil.