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Case or Chassis
Adhesive
Transfer Tape
Cushion Tape
Linear Resonant
Actuator (LRA)
Actuator Support
Structure or Wall
Mounting Guidelines
5
Mounting Guidelines
In general, actuators should be mounted in an application using a combination of adhesion and
compression. The adhesive ensures the actuator remains in place and the compression mitigates
manufacturing tolerances and ensures that the vibration is transferred to the body of the device.
Figure 14. LRA Mounting Stack Up
Actuators are often mounted using an adhesive transfer tape from 3M. This double-sided tape is very
strong and intended to withstand a long lifetime of vibration. Many actuator manufacturers provide the
option to include the adhesive tape on the actuator for production builds.
Table 4. Adhesive Transfer Tape for Mounting Actuators
Part Number
Manufacturer
Description
3-5-468MP
3M
Adhesive transfer tape
Alternatively, some ERM and LRA actuators can be soldered to the PCB board directly to ensure long
lasting vibration performance; however, care must be taken to ensure that vibration is transferred from the
PCB to the chassis of the device.
6
Mounting an Actuator for Testing
The acceleration of an actuator often needs to be measured outside of the final system or application to
compare actuator strengths, run life-tests, or create haptic effects. The best way to measure acceleration
is to mount the actuator on a fixture that has similar mass to the final application. We call this a haptic test
fixture. To do this:
1. Create a test fixture that has a similar size and weight as the final application. An aluminum or similar
material block works well for most applications.
2. Place the actuator in a similar location as it would appear in the final application and attach it to the
mass using strong adhesive tape, epoxy, or glue.
3. Place the test fixture on a material that can isolate the vibration such as a piece of foam or a silicone
gel. The mechanical isolation prevents rattling and transferring vibration to the table. Test the material
and make sure it roughly mimics the final application environment.
4. Place the accelerometer board on the fixture using the adhesive tape, near the actuator and begin
measuring.
To measure the acceleration of an actuator for use inside a smartphone, place the actuator on a 100 g
block that has a similar size and shape as the phone. Next, place the block on a piece of packing or ESD
foam to represent a hand, which is where a phone is normally held. Finally, measure the acceleration of
the block on the foam and compare it to when a person holds it in their hand.
9
SLOU402 – June 2015
DRV-ACC16-EVM Accelerometer User’s Guide
Copyright © 2015, Texas Instruments Incorporated