Interlink Electronics Micro Joystick - Manual (Page 16)

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14
MicroJoystick
Integration Guide
5.1.4 Method 4: Adhesive
One of the simplest ways of mounting a MicroJoystick to a flat surface is to use a pressure
sensitive adhesive. Companies such as 3M Corporation make such adhesives, and can
recommend a specific product. Generally, the adhesive bond becomes stronger over time,
reaching its maximum in about two days. If you will need to use the holes for screws to register
the MicroJoystick (in addition to the adhesive), then you may need to cut out the adhesive strip
where it overlays the holes.
5.1.5 Method 5: Heat-stake pins
Heat-stake pins may also be used to mount the MicroJoystick to a flat surface. A horn can be
designed to melt plastic into the three holes to secure the base into place.
5.2 Custom Design Parameters
Interlink Electronics strongly recommends using one of the mounting methods described in
section 5.1. However, these methods may not be appropriate for all systems. If you do need to
design an alternative mounting method, please review the design parameters given below.
Note: These design parameters should be used when designing any mounting method. Before
proceeding to production, any mounting method should be carefully reviewed and tested to
ensure that it does not impair the performance of the MicroJoystick (e.g., introduce bias, cause
preloads on the MicroJoystick, etc.) or introduce other unwanted effects.
Flatness of Mounting Surface
If the MicroJoystick is mounted to a flat surface, the surface should be flat within 0.013mm As
detailed in section 5.1.3, a hole or indentation in the mounting surface can help reduce the
unwanted effects of the mounting surface on the MicroJoystick.
Screwing into Two Surface
Do NOT screw into two surfaces. If screws are used to mount the MicroJoystick, the screws
should only thread into one surface. For example, if the MicroJoystick is mounted to a mounting
surface, the mounting screws should only thread into the mounting surface and not the
MicroJoystick’s base. Threading into two surfaces (i.e., the MicroJoystick’s base and the
mounting surface) can cause unwanted forces to be applied to the MicroJoystick. These forces
could cause cursor movement or cursor drift. Please refer to section 5.1.3.
ESD
When designing a mounting system, care should be taken to consider your electro static
discharge (ESD) requirements. The exposed connecting traces should be properly insulated
against any direct source of static electricity. Your mounting system should be designed with a
large enough dielectric strength (i.e., length of air path from the ESD probe to the conductive
traces on the MicroJoystick’s base plus any additional dielectric insulation) to prevent unwanted
ESD effects. Generally, the further you can bury the MicroJoystick into the mounting surface, the
better your protection against ESD.
Whenever possible, the mounting methods in Section 5.1 have been designed with long or
lengthened air paths from the ESD probe to the MicroJoystick’s conductive traces. Testing is
based on IEC 61000-4-2 requirements using only the air discharge method. The MicroJoystick
with “captuator hidden” mounting method was subjected to 5, 10 and 15 KV electrostatic
discharges. ESD testing should be repeated after the actual integration. Actual ESD tolerance or
resistance is subject to the integration design. Please see Figure 5, “MicroJoystick ESD Test
Information.”