As discussed in Section 2, it is important to position the magnet in such a way to utilize as much of the linear input range of the sensor without saturating the inputs. Sweeping the magnet position near a 3D Hall-effect sensor will produce a behavior similar to what is shown in Example Lever Input Field. It is typical that a component of the field vector will have a somewhat triangular or S shape, while the other two components will have a bell shape. The magnitude of each vector component will depend on alignment.

Figure 3-5 Example Lever Input Field

To maximize the input range for a control such as the turn indicator stalk, the mid-point position for the magnet must be centered above the magnet. For this case, where the magnet location is not placed on the rotating fulcrum of the control, it becomes necessary to use a single multi-axis sensing device similar to what was presented in Section 2, using one of the configurations presented in Figure 3-1

A first reason for this requirement can be observed in Example Lever Input Field. As the lever pivots to either +15 or -15 degrees relative to the idle position, we see the challenge that aliasing can create when observing B_z. Even if using the B_y component, there are positions above +/- 10 degrees from center where the input field can be mapped to a second location.

Additionally, if only observing a single axis, the lever pull for flash-to-pass will increase the distance between the magnet and sensor. If only using a single axis of sensitivity, this motion can also become ambiguous and can be confused with a left or right turn setting.