Electronic Design
Natural User Interface Employs Sensor Integration

Natural User Interface Employs Sensor Integration

MEMS sensors can be notoriosly hard to get consistent, long term results. It is one reason Hillcrest Labs' Freespace MotionEngine software makes a difference when coupled with an array of 3D MEMS sensors for Analog Devices. Multiple sensors are included in Hillcrest Labs' new Scoop Pointer (Fig. 1) that is available to end users as well as OEMs.

The Scoop and Hillcrest Labs' latest sensor modules utilizes MEMS inertial, gyroscope and magnetic compass devices. It provides cursor as well as non-cursor and linear acceleration information that can be used to implement a natural point and shoot user interface as well as providing the ability to detect motion gestures.

The Scoop supports wireless connectivity and could be combined with RF4CE devices since the Scoop provides standalone sensing versus alternative 3D sensing technology like Sixense's magnetic-based sensor system (see Sixense Sensor Provides Real 3D Positioning) that requires a base station or Microsoft's Kinect that is based on Primesense's 3D camera technology (see How Microsoft’s PrimeSense-based Kinect Really Works). These provide 3D position information as well as movement and orientation but that is not always necessary for many applications. Likewise, there is a placement issue that can be significant in many environments. The Scoop also works with devices like Roku's Roku 2 HD streaming media box (see Consumer Electronics Series: Roku Netflix Player) as well as LG Smart TVs. Roku is taking advantage of the interface to drive games.

The Scoop, and Hillcrest Labs' sensors, can be used to track a cursor on an HDTV screen and this is highlighted by its use with Hillcrest Labs' Mozillab-based Kylo web browser (Fig.2). Kylo can be used with a range of user interface devices like Scoop and it is available as an OEM products as well.

The Scoop is not Hillcrest Labs' first device. It was showing it's novel Loop Pointer (Fig. 3) at CES 2007 (watch HoME YouTube Demo and 'Remote' from CES 2007 on Engineering TV). This was based on an earlier version of the Freespace software.

Freespace MotionEngine is designed to work with data from the MEMS sensors. These adjust for temperature and time to provide stable and consistent output. Part of the process is also detailed examination of the MEMS specifications to understand what the specifications like average or min/max results really mean across time and a range of devices.

The result is the 9mm by 19mm by 2.5mm FSM-SENS-1 sensor module. This is designed to work with a microcontroller that would run some or all of the Freespace MotionEngine. An alternative is the slightly larger smart module, the FSM-SI-2. This adds an STMicroelectronics' STM32 32-bit Cortex-M3 microcontroller (see Playing Games With the STM32). It supports cursor movement as well as angular and velocity information but does not include the gesture library support.

The software overhead is not significant although a 32-bit micro helps with calculations. Also, the Freespace MotionEngine libraries are designed to be split so some of it might reside on a control device while the rest runs on a host device. Hillcrest Labs uses their own gesture libraries and API. The module interface uses SPI but it can be linked to a range of wireless devices. The reference kits include USB, Bluetooth, and 2.4GHz RF support. The FSM-SI-2 has micro USB connection. Hillcrest Labs is also supporting Texas Instruments' wireless solutions for remote controls.

The modules and software can be used for a range of applications from robot control to virtual reality. The Scoop Pointer uses a 3-axis gyro and 3-axis accelerometer. It also has 9 buttons and scroll wheel reflecting its intended use as an smart TV remote control and game controller. Scoop is bundled with Kylo for HTPC integrators.

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