Download body motion capture using multiple inertial sensors

Bluetooth
802.15.4
I/O
External
Expensions
I/O
CPU
I/O
Flash Memory
I/O
Accelerometer
Figure 4.1
Gyroscope
SHIMMER System Diagram
The detailed functional description of each subsystem will be discussed in this
chapter. They are microcontroller, accelerometer, gyroscope, wireless communication
module, IO and memory expansions.
4.1.1 MSP430F1611 Mixed-Signal Microcontroller
The processor used in SHIMMER system is the Texas Instruments 16-bit ultra-lowpower microcontroller MSP430F1611 which is designed in portable measurement
applications. It has two built-in 16-bit timers, a fast 12-bit ADC, dual 12-bit DACs, one
or two Universal Synchronous/Asynchronous Receiver/Transmitter (USART), I2C, DMA
and 48 I/O pins. The MSP430F1611 microcontroller offers extended 10Kbyte RAM and
48Kbyte flash for memory-intensive applications and large C-stack requirements [39]. In
this body motion capture system, the 8-channel 12-bit ADC is used to convert the data
measured from the gyroscope from analog to digital signal. The three-axis gyroscope data
and three-axis accelerometer data conversion use 6 channels of the microcontroller’s
built-in ADC.
4.1.2 MMA7361 3-axis MEMS (Micro Electro Mechanical systems)
Accelerometer
The MMA7361L is a low-power, low-profile capacitive, 3-axis micromachined
accelerometer produced by Freescale Semiconductor Inc.. Typical features include signal
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