Modern Healthcare With Wearable Sensors and Wireless Technology

1.1 Methodology

Figure 1.

Block diagram for patient fall monitoring system

The prototype developed shown in Figure 1 consists of a set of biomedical sensor attached to the body of the person whose health condition is to be monitored. In this work, three axis accelerometer are used to detect the fall of the person. These sensors are connected to LPC2148 Advanced RISC Machine (ARM) micro controller. The microcontroller receives the signals from the sensors and processes the data and checks for the condition of the person. If the condition is normal then the microcontroller keeps on repeating the same process of receiving the data from the sensors and monitoring the position of the person. Whenever the condition steps out the normal range it checks for two or more values, if still the same condition prevails microcontroller sends alert messages to the care takers and concerned health care professionals about the unusual health condition of the person. Once doctor receives message and immediate response can be provided to the affected person. The SMS is sent in response to the person in need of help through the GSM modem which receives message and medicine name is displayed on LCD connected to controller through port pins.

1.2 ARM LPC2148 Microcontroller

NXP Semiconductors (formerly Philips Semiconductors) designed a 32 bit microcontroller grouped under LPC series. It has the CPU with emulation and debugging support and also with In-circuit programming features which supports 32 kB to 512 kB high speed flash memory. The microcontroller used in the prototype is with 128 bit wide memory interface with pipelined architecture which enables faster code execution. There is an alternative instruction set to ARM 32 bit is Thumb 16 bit which is ideal for critical code size applications that reduces code by more than 30% with minimal performance penalty (NXP Semiconductors 2011).

Each microcontroller unit consists of the processor core which is the heart of the core, memories includes static RAM (SRAM) memory, flash memory. In some higher applications cache memory is also used for storage purposed. It also support serial communications interfaces ranging from a Universal Serial Bus (USB) 2.0 Full-speed device, multiple Universal Asynchronous Receiver and Transmitter (UART), Serial Peripheral Interface (SPI), Synchronous serial port (SSP) to Inter Integrated Circuit (I2C) and on-chip SRAM of 8 kB up to 40 kB. These added interface enables the ARM based products well suited for the applications in networking and also in imaging. Advanced ARM machined are providing both with large buffer size and high processing power. All ARM based microcontrollers are provided with 32-bit timers, 10-bit ADC/DAC, Real Time Clock (RTC). With the help of 45 fast GPIO lines with external interrupt pins, makes the ARM based controller suitable for industrial control and medical systems.