4 System overview
Doc. ID 4374_139 v1.1
Page 22
The LIS3DH 3-axis ultra-low power accelerometer from ST Microelectronics is used to detect user interaction
and wake up the MCU, which in turn wakes up the rest of the system. This provides intelligent power-saving
(see Intelligent power saving on page 24).
Use of this module is optional. See the firmware documentation for details.
4.1.4 Free-space navigation
The remote control includes a three-axis gyro and three-axis accelerometer combo circuit that can be used as
a free-space navigation sensor, enabling the user to move a mouse cursor through gesturing with the remote
control.
The gyro and accelerometer combo circuit is the ICM-20608 from InvenSense
®
. The gyro and accelerometer
circuit is used as an input device for a SmartMotion
®
firmware library from InvenSense that is integrated into
the Smart Remote 3 firmware. Output data from the InvenSense library is fitted into a HID mouse report and
sent to the host.
Important: The in-air pointing functionality is only provided as precompiled HEX files. To use the
Smart-Motion library in your design, please contact InvenSense
®
or visit the InvenSense
®
Developers
Corner (sign up required).
Basic use
To enable the free-space navigation feature, press the orange button between the Channel + and Volume +
buttons (see Figure 5: Enable the free-space navigation feature on page 22). The remote control will then
switch from trackpad to free-space navigation mode. In this mode, acceleration and rotational data from the
gyro is processed by the SmartMotion firmware library.
When operating in the free-space navigation mode, the button just above the volume control is the Left
mouse button and the button just above the program selector is the Right mouse, enabling point and click
functionality. To deactivate free-space mode and go back to trackpad mode, press the orange button again.
The free-space navigation mode will also be deactivated if the remote control has not moved in 7 seconds.
Figure 5: Enable the free-space navigation feature
Movement of the remote control is translated into two-dimensional mouse cursor movement. Rotation
around the x-axis (upward and downward movements) of the remote control will lead to vertical mouse cursor
To Next Page
Loading...