Design of a wireless platform for wearable and home automation applications

Title from PDF of title page, viewed on October 2, 2012Thesis advisor: Walter D. León-SalasVitaIncludes bibliographic references (p. 147-[151])Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2012In the recent past, a great deal of attention has been given to wireless sensors. Wireless sensors enable a multitude of applications such as environmental monitoring, medical care, disaster response, home automation, urban scale monitoring, gaming etc. These small, low-power, multifunctional sensors includes sensing, data processing and communication components representing a significant improvement over the traditional sensors. The two attractive wireless sensor applications investigated in this thesis are wearable sensors for bio-medical applications and a ZigBee wireless network for home automation applications. The targeted bio-medical application is bone strain monitoring. The current setup to collect strain data is composed of a data acquisition unit connected to a bench top load instrument. For accurate measurements the lab animals have to be sedated and immobilized in the current setup which is also bulky. A telemetry unit equipped with strain gages designed for implantable measurement of bone strain was designed to address this problem. The measurements collected by an implantable telemetry unit are of high interest to orthopedic researchers who wish to know the load acting on an orthopedic implant and hence to help guide the rehabilitation outcomes in a patient. This thesis describes two small telemetry units with multiple configurable sensor channels which can be used to sense resistance and voltage. Thus, the designed units can be used in home energy monitoring applications as well. The units have low power consumption and were designed using off-the-shelf components. Their dimensions are 24 mm x 13 mm and 10 mm x 10 mm. The sensor signals are multiplexed, modulated and transmitted to a remote computer by means of a radio transceiver. Besides measuring strain integrated levels the telemetry units can also measure acceleration in 3 axes. Wireless battery charging is another feature that was included in our design which is a key feature for surgically implanted devices. To show that our telemetry units has comparable accuracy and compactness to the current setup, we present the readings from both setups. A ZigBee wireless sensor network to monitor and control home appliances was designed and successfully tested. A central control unit is the coordinator which sets up the network and configures the ZigBee network parameters. The battery powered sensors are configured as end-devices which periodically report sensor data such as light, temperature, accelerometer and energy consumption values to the coordinator. Any home appliance limited to less than 10 Amps in the ZigBee network can be turned on or off from the central control unit. With bidirectional communication achieved between the central control unit and the end-device, we were able to achieve a home automation system.Introduction -- Background -- Telemetry unit architecture -- Data collection and results -- Conclusion and future work -- Appendix A.1. Four layer PCB layout of the eight channel telemetry unit -- Appendix A.2. Four layer PCB layout of the four channel telemetry uni

An embedded multichannel telemetry unit for bone strain monitoring

Abstract An embedded telemetry unit for bone strain monitoring is presented. The telemetry unit is designed using commercially available components to lower design time and manufacturing costs. The unit can read up to eight strain gauges and measures 2.4 cm × 1.3 cm × 0.7 cm. The unit is powered from a small Li-polymer battery that can be recharged wirelessly through tissue, making it suitable for implanted applications. The average current consumption of the telemetry unit is 1.9 mA while transmitting at a rate of 75 kps and at a sampling rate of 20 Hz. The telemetry unit also features a power-down mode to minimize its power consumption when it is not in use. The telemetry unit operates in the 915-MHz ISM radio band. The unit was tested in an ex vivo setting with an ulna bone from a mouse and in a simulated in vivo setting with a phantom tissue. Bone strain data collected ex vivo shows that the telemetry unit can measure strain with an accuracy comparable to a more expensive benchtop data acquisition system.Peer Reviewe

Different Features of Cholera in Malnourished and Non-Malnourished Children: Analysis of 20 Years of Surveillance Data from a Large Diarrheal Disease Hospital in Urban Bangladesh

Malnourished children are more prone to infectious diseases including severe diarrhea compared to non-malnourished children. However, data are scarce on differences in the presentation in such children. We aimed to identify clinical differentials among children with cholera with or without malnutrition. Data were extracted from the diarrheal disease surveillance system (DDSS) of Dhaka Hospital of International Centre for Diarrheal Disease Research, Bangladesh (icddr,b) from January 2001 to December 2020. Among children under five in DDSS, cholera positive (culture confirmed) malnourished children (WAZ, WL/HZ or L/HAZ ˂ −2) were considered as cases (n = 920) and children with cholera but non-malnourished (WAZ, WL/HZ or L/HAZ ≥−2.00 to ≤+2.00) were controls (n = 586). After adjusting for potential confounders such as maternal illiteracy, day labor fathers, maternal employment, slum dwelling, non-sanitary latrine use, use of untreated water, and history of cough, it was revealed that malnourished cholera children significantly more often presented in hospital during evening hours (6 p.m. to 12 mid-night) (p p 24 h history of diarrheal duration (p p p < 0.05). The study results underscore the importance of understanding of basic differences in the presentation of severity of cholera in malnourished children for prompt identification and subsequent management of these vulnerable children