The presentation will comprise the development of two stray field immune magnet-sensor systems. It will cover the methods in their pre-design process as specific FEM simulations and 3D-Hall sensor measurement before realizing any hardware. Stray field immune sensors are often built by sensor pairs using the gradient principle. So, first stage tests including simulations and Hall measurements on different traces close the magnet and calculating potential sensor pair outputs are very valuable. Both can prove the viability of a devised systems and when successful the practical realization can be initiated. The whole way from pre-design investigations up to the hardware realization of a first sensor will be sketched in the presentation.