| Style "FRP" Sensor -- Patent 5,115,194 is now expired due to non payment of maintenance fees. One can now use the Flux Return Path screw concept, shown in Figure 7A, with this magnetic circuit as shown. There are other patents that use a flux return path screw concept, so if you are using this concept for anything other than instructional projects, school lab projects, or robot hobby projects, check it out so there are no patent conflicts. A standard 2-56 machine screw from a model airplane hobby shop will work very well. |
| Appendix A |
This figure shows another method of adjusting the magnetic flux density level of the Hall Effect sensor's
magnetic circuit. Instead of moving the magnetic circuit's position with reference to the Hall Effect
sensor IC, one can mount the Hall Effect sensor in a fixed location with reference to the magnets and
adjust the air gap between the Hall Effect sensor and a steel screw which is located directly behind the
Hall Effect sensor. A hold can be drilled in the pole piece and tapped for a 2-56 machine screw. The
method of adjusting the magnetic flux density level is presented in U. S. Patent 5,115,194.
magnetic circuit. Instead of moving the magnetic circuit's position with reference to the Hall Effect
sensor IC, one can mount the Hall Effect sensor in a fixed location with reference to the magnets and
adjust the air gap between the Hall Effect sensor and a steel screw which is located directly behind the
Hall Effect sensor. A hold can be drilled in the pole piece and tapped for a 2-56 machine screw. The
method of adjusting the magnetic flux density level is presented in U. S. Patent 5,115,194.