The purpose of the thesis was to develop an optically sensitive target for a laser gun for safe sports shooting training at home. The target is shot at with a laser beam modulated at 1 kHz. The laser light scatters off a diffuse white target disc and arrives at four symmetrically positioned photodiodes. We sample the four signals at 40 kS/s, phase-lock on their sum and calculate their amplitudes. By comparing the amplitudes we determine the position of the laser spot on the target disc. In this way we achieved a 1.2 mm resolution of the laser spot position.
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