The SHIMMER™ wireless sensor platform was originally developed by Intel. It was licensed to Irish company Realtime Technologies in 2008. SHIMMER™ is comprised of a baseboard that provides computational, data storage, communications, and daughterboard connection capabilities. The core functionality of the SHIMMER™ platform is extended via a range of daughterboards that provide kinematic, physiological, and ambient sensing capabilities. This range of contact and non-sensing capabilities is reliable in clinical and in home-based usage scenarios.
SHIMMER™ Design
The SHIMMER™ baseboard features a low power of Texas Instruments MSP430 MCU (Microcontroller Unit). The primary advantages of the MCU are its extremely low power requirements during periods of inactivity and it is proven in medical sensing applications. The baseboard also has a Freescale Semiconductor 3-axis (XYZ) accelerometer suitable for low-power kinematic applications and a passive tilt/vibration sensor (SQ-SEN-200 – Signal Quest). The tilt/vibration sensor is sensitive to both tilt (static acceleration) and vibration (dynamic acceleration). It can be used to ‘wake’ the platform from low power sleep mode.
The SHIMMER™ base board has the ability to communicate as a wireless platform. It features two radios which can be selected depending on the application requirements:
- Bluetooth® radio (Roving Networks RN-41* Class 2 Bluetooth module)
- 802.15.4 Radio (modules (Chipcon CC2420 radio transceiver and a gigaAnt 2.4GHz Rufa antenna).
The SHIMMER™ baseboard also features a MicroSD card slot that supports up to two Gbytes of flash memory. This allows sensor data to be written to the MicroSD and downloaded for analysis at a later date.
SHIMMER™ Daughterboards
The sensing capabilities of the SHIMMER™ baseboard are extended by the connection of daughterboards via a Hirose connector on the baseboard. Currently there are seven daughterboards available for SHIMMER™.
Kinematic Sensing Physiological Sensing Ambient Sensing
Gyroscope ECG PIR Motion
Magnetometer GSR Temperature
EMG Light
SHIMMER™ Firmware
Firmware provides the low-level capabilities within the SHIMMER™ platform to control the device functions. All SHIMMER™ firmware has developed by using TinyOS and released into the public domain via SourceForge. Firmware running on the sensor platform provides local processing of the sensed data, local storage of the data if required, and communications of the data to a higher-level application such as BioMOBIUS for advanced signal processing, display and data persistence.