The most recent development based on the CC430 is TI’s eZ430-Chronos sports watch (Fig. 4), which is designed to enable many applications beyond athletics. “We have shipped 110,000 eZ430 development kits,” says Adrian Valenzuela, the MSP430 marketing manager (see “Low-Cost Kits Make Evaluation Faster”). “With this development platform, we are trying to enable many more applications like medical (e.g., heart rate, pulse rate, blood glucose level, and temperature monitoring), home automation, hobbies, etc.”
Microchip Technology has tweaked its nanoWatt XLP extremely low-power technology (Fig. 5) in its PIC microcontrollers for use in home healthcare devices like blood glucose meters. Its PIC16, 18, and 24F microcontrollers draw just 100 nA in power-down mode and feature 800-nA watchdog timers and real-time clocks and calendars.
Some companies use flash memory microcontroller units optimized for low power dissipation for handheld home healthcare equipment like blood glucose monitors. The 16-bit all-flash MCUs from NEC Electronics are based on the company’s 78k0R CPU core and operate from 3.3 to 5 V. They feature an integrated LCD driver, 12-bit analog-to-digital and digital-to-analog converters (ADCs and DACs), op amps, and a voltage reference. Their 1.2-µA standby current was achieved by de-activating the CPU when the LCD is enabled in that mode.
“We’ve been in the blood glucose meter business since the early 1990s and understand the low-power requirements of such medical equipment,” says Michael Clodfelter, principal technical marketing engineer at NEC. “The low-power standby mode specifications in the nA range being bandied about by some MCU manufacturers are a bit of overkill. In reality, about 1 µA is more than enough, for the standby mode, for long battery life in a blood glucose meter.”
Clodfelter also sees a trend toward using 32-bit MCUs in portable medical home equipment to provide even higher levels of accuracy. In fact, NEC offers its 32-bit all-flash V850ES (Fig. 6), which consumes just 900 mW of power/Dhrystone, for blood glucose meters. The microcontroller’s pipelined architecture executes up to 43 Dhrystone MIPS (1.1) at clock speeds from 5 to 20 MHz.
RESPIRATORY MONITORING
Portable instruments for respiratory monitoring are among the more recent healthcare products finding their way into the home. Some of the more notable respiratory ailments include chronic pulmonary compulsive disorder (COPD), asthma, and sleep apnea. More than 300 million people worldwide suffer from asthma.
For asthma patients, KarmelSonix has introduced the Wheezometer. This personal asthmatic assessment device is based on Analog Devices’ 400-MHz BF524 Blackfin DSP. The handheld unit is placed against a patient’s throat. Piezoelectric sensors then pick up air flow irregularity data from the patient’s breathing and feed it to the DSP. The processor determines the patient’s wheeze rate, which is defined as the respiratory cycle duration occupied by wheezing. KarmelSonix says that the wheeze rate is a dynamic and significant asthma attack measure of an asthma patient.
KarmelSonix’s patented software algorithms apply strict criteria to determine the presence of wheezing. The company says that guidelines supplied by computerized respiratory sound analysis (CORSA) define these criteria.
“Having a wheezometer is a real convenience even beyond the home. Such a portable piece of equipment can be carried in one’s backpack. The meter’s output data can then be downloaded, via a USB port on a laptop computer, to a physician or medical provider, from just about anywhere,” explains Tony Zarola, strategic marketing manager at Analog Devices. “We’re looking to use the Blackfin DSP in EKG wireless monitoring applications, via USB ports.”
To expedite the development of portable home healthcare medical equipment, TI is offering development kits based on the TMS320VC5505 DSP. TI says the kits accelerate time-to-market by up to eight months. Each kit includes hardware and software design tools, including schematics, sample application code, medical-specific algorithms, and collateral support.
Royal Philips Electronics offers an intelligent sleep apnea therapy system for home healthcare. About the size of clock radio (7 by 5.5 by 4 in.), the Reprionics Sleep Therapy System provides of therapy options for patients with mild to severe forms of sleep apnea. The unit works on the Philips-developed positive airway pressure principle by delivering a gentle flow of pressurized air through a face mask to keep the patient’s airway open.
“This is our most sophisticated offering to date, in sleep apnea therapy, and it comes at a time when patient compliance matters most,” says Donald Spence, CEO of Philips’ home healthcare solutions.
Philips also supplies the Trilogy 100 portable at-home life-support ventilator for adult and pediatric use. It is designed to help caregivers and clinicians administer patient care in the home as well in skilled nursing facilities.
Additionally, Philips is promoting home healthcare medical platform display terminals that will facilitate remote patient management delivered through the patient’s home TV or the Internet. That’s what the company’s Motiva interactive platform does. In addition to monitoring vital signs, it can deliver educational information and motivational messages. It can be used for health-related surveys as well.
Intel recently released for testing its Health Guide, a type of PC for medical information monitoring and communication (see “Electronics Helps Foster Decentralized Healthcare” ). It monitors the vital signs of elderly patients with chronic conditions and provides details via the Web to a remotely located medical provider.
Intel and GE, both heavyweight members of the Continua Health Alliance, recently joined forces to focus on healthcare issues for the home as well as assisted-living facilities. Formed in 2006, the organization aims to address the lifestyles, health, and demographic trends contributing to the skyrocketing costs of healthcare.
The Continua Health Alliance consists of leading healthcare providers, insurance companies, hospitals, pharmaceutical companies, semiconductor IC companies, and sports gear and medical equipment manufacturers. It is trying to standardize wireless and wired communications protocols, enabling many IC and medical equipment providers to actively participate in the portable home healthcare monitoring equipment market.
THE ROLE OF INTEROPERABILITY
Interoperability is a key goal for home healthcare equipment. The medical equipment and IC communities recognize that for home healthcare devices to proliferate, they must be able to cost-effectively, securely, and rapidly communicate with each other and other sources of patient information.
“Interoperability is a major issue that will enable the portable home healthcare market to grow further,” says Rajesh Verma, TI’s business development manager for MCU medical solutions. “As part of that effort, we’re involved with the Continua Health Alliance to standardize on all workable communications protocols.”