RedRock Switch Angular Sensitivity Map – A Coto Technology Tech Tip

Learn more about the angular sensitivity map of the RedRock MEMS-based reed switch.

The RS-A-2515 microfabricated reed switch (Figure 1) has a single cantilever blade and an offset contact gap, revealed when the wafer cap is removed (Figure 2).  This asymmetric design results in the switch having considerably higher magnetic closure sensitivity in certain directions relative to others.  Coto specifies the normal closure sensitivity for a magnetic field at right angles to the long axis of the switch, with the orientation dot away from the source of the field.  However, users requiring more sensitivity can take advantage of the non-isotropic nature of the field response to effectively boost the magnetic sensitivity of the switch and hence the distance at which a particular magnet will close the switch.  The asymmetric response pattern is also useful in applications where external stray magnetic fields may be present.  The “lighthouse beam” magnetic response of the switch allows the direction of peak magnetic sensitivity to be pointed directly at a driver magnet, while minimizing the effects of stray magnetic fields that are off the main sensitivity axis.