Posts Tagged ‘accelerometer’

Shimmer Research has added to their sensing range with the addition of a GPS expansion module for the Shimmer platform. The module provides accurate location and global time to sensing applications, along with ambient data via a pressure / temperature sensor integrated onto the GPS daughter-board.

The GPS module maintains the wearable form factor associated with Shimmer, with a small size (53mm x 32mm x 23mm) and light overall weight (32grams). The assembled unit provides an impressive list of sensing capabilities combining Shimmer’s integrated motion sensors (Accelerometer and Tilt/Vibration), with GPS, Temperature, and Barometric pressure sensing.

The module has received robust pre-launch interest from industry and researchers, with the Shimmer GPS already being used for people tracking, sports informatics, and maritime monitoring. Enquiries have also been received in the areas of transport, logistics, defence, and the social sciences with particular attention given to the ability to develop globally synchronized sensing systems via the GPS’s accurate timing capacity.

One of the key features of the module is the provision of raw data, with no proprietary software or predefined analysis parameters.  As outlined by Kieran Daly (VP of Business Development) the ‘Shimmer GPS hardware enables researchers to interpret data specific to their application requirements, unlike many end user, domain focused GPS products currently available. For industry, the Shimmer GPS module can be used as the hardware to develop customised commercial solutions with a faster time to market – driving business growth’.

Driver and test application code for the GPS module are available in the TinyOS Sourceforge/Googlecode repositories, with a user manual available to new and existing customers via the download section of the website. Separate drivers provide support for both the GPS and Pressure Sensor modules, and test applications demonstrate the use of both.

The GPS Development Kit, and GPS Module are now available, and can be purchased via our online store.

Keep up to date with the latest news and announcements:

Shimmer 2R, the latest revision of the Shimmer platform has been released and is now available to purchase from our online store. Changes to the platform include a lower power Accelerometer, new Bluetooth radio module, new 802.15.4 radio module, and a smaller more functional enclosure.

The Shimmer 2R platform has improved battery voltage monitoring, and the ability to measure/calculate instantaneous operating current. This new functionality will benefit customers seeking to develop resource aware applications. The new 802.15.4 radio module, developed by Shimmer Research and titled SR7, has FCC, IC, and ETSI certification and is also utilised on the recently launch Span Platform for low power standards based communication.

New Features of the Shimmer 2R Platform:

• New 3 Axis Accelerometer: Freescale MMA7361 1.5/6g Micropower MEMs Accelerometer

• New Shimmer Research SR7 Radio Module: 802.15.4 Radio Module with Chipcon CC2420, Chip Antenna. The SR7 has FCC, IC, and ETSI Certification.

• New Class 2 Bluetooth™ Radio: Roving Networks RN-42 with soft-power control and improved low-power and master-mode.

• Power Monitoring: Improved battery voltage monitoring and the ability to measure/calculate operating current.

• More Functional Case Design.

The release of Shimmer 2R coincides with the release of a full range of new enclosures. The new case design is 25% smaller in volume than the previous generation Shimmer unit, and offers greater functionality on the expansion modules.

For more details on the Shimmer 2R platform download the capabilities overview, or for registered users of our members section, download the Shimmer 2R manual.

Having used Shimmer in their studies in conjunction with the TRIL (Technology for Independent Living) centre, Intel has recently published a paper on the validation of the Shimmer ECG, Motion, and GSR daughter cards. The operation of the Shimmer baseboard and daughter cards has been tested through a number of validation processes to determine the accuracy of the boards’ function and their usefulness for biomedical-orientated research applications.

ECG Validation

A number of tests were carried out to validate the Shimmer ECG daughter card as a valid tool for acquiring ambulatory ECG. The tests included the validation of the ECG amplifier and ADC performance by using calibrated input signals as well as an ECG recording from a healthy non-resting subject. Another test carried out was a 5.9 minute ECG recording containing 503 heart beats from a non-resting healthy subject during a moderate walk. The information was captured by the Shimmer ECG and also captured by a Medilog Holter monitoring system. The results indicate that the Shimmer ECG can be used to acquire ambulatory ECG from resting and non-resting human subjects for research application purposes.

Kinematic Validation

To validate the Shimmer platform for use in studies of human gait analysis, temporal gait parameters derived from a tri-axial gyroscope on the Shimmer platform were compared against those acquired simultaneously, by using the codamotion analysis system from Charnwood Dynamics Ltd., UK.

The gait of one normal healthy adult male (age 25) was measured simultaneously by using two Shimmer sensors placed on each shank and the Cartesian Optoelectronic Dynamic Anthropometer (CODA) motion analysis system. Data was recorded whilst the subject performed multiple over-ground walking and running trials along a 15-meter walkway in a motion analysis laboratory. Heel strike and toe-off characteristic points derived from the Shimmer and CODA systems were used to calculate the three temporal gait parameters listed below:

• Stride time
• Stance time
• Swing time

Results show an intraclass correlation coefficient (ICC(2,k)) [64] greater than 0.85 in stride, swing, and stance times for ten walking trials and four running trials. These results suggest that the Shimmer platform is a versatile cost-effective tool for use in temporal gait analysis.

GSR Validation

The Shimmer galvanic skin response (GSR) sensor contains an internal resistor network that works as a potential divider and provides a voltage that can be converted by the Shimmer’s ADC to a 12-bit value, used to measure external skin resistance. All skin resistance values were calculated in the Shimmer platform firmware and transmitted to a BioMOBIUS patch for real-time display and persistence to file. The sensor performance was correlated with a commercial Nexus-10 system (Mind Media BV) utilizing a series of known resistors from 10K Ω to 2.2M Ω. Shimmer GSR demonstrated an average mean percentage error of 2.3 percent versus the commercial Nexus-10 that had an average mean error of 4.1 percent.

Shimmer Research is proud to announce the launch of the next generation Shimmer, which has evolved from Shimmer 1.3 to offer new features and functionality to users of the platform.

The latest revision of the Shimmer platform adds improvements based on years of field trials and deployments. The most dramatic change is a patent-pending direct-to-host data transfer path from Shimmer’s MicroSD card to hasten data offload, minimize user training, and provide fail-safe data access. Power control features have been added including soft-power switching and low-battery shutdown. Finally a passive vibration sensor was added— this sensor efficiently signals when the device is in use.

Other new features on the Shimmer 2 platform are:

• Reset/User Programmable on/off switch
• SD Card with data-path MUX for full-speed host transfer when docked and soft-power control with dock detection over-ride
• SD data bypass – full FAT FS for SD access when the shimmer is docked
• Tilt/vibration sensor
• Improved plastics and enclosure

Shimmer (rev 2.0) will also be compatible with the existing Shimmer 1.3 family of products and accessories to insure easy of integration into existing Shimmer projects.

Download the PDF document to see a full Capabilities Overview.

Download the PDF document to answer any Legacy Support Questions.

To purchase the platform today, please visit our Online Store.