In a micro-optical deflection system, the sensory properties of the ferromagnetic shape memory alloy Ni-Mn-Ga are to be investigated. An electro-thermally activatable thin-film bending actuator, pre-aligned by a permanent magnet, is used for beam deflection. The aim of this work is to examine the suitability of the magnetoresistive material for position determination. For comparative evaluation, capacitive and resistive reference sensors are utilized.