Wireless transceiver

Recent progresses in micro- and nanotechnology have led to the design of implantable, swallowable, wearable, or portable wireless biosensors to continuously monitor and detect important physiological parameters. The miniaturization and integration of biosensors, readout circuits, embedded microcontrollers, and wireless transceivers on a single chip have opened the way for new possibilities in medical applications. 

The smart shirt Sensatex, a New York-based company, is developing a shirt that is used to monitor patients vital signs. The shirt is made of an electro-optical fabric that transfers data from the wearer to the garment. A transceiver on the shirt records the data and sends it to a wireless gateway, from which it can be transmitted to the doctor. 

A wide range of conttol systems is used in household appliances. A standard conttol loop consists of sensors, control units and actuators. The appliances become more powerful and efficient, as the technology is developed and integrated into microsystems. Matchbox-sized sensors can be equipped with wireless radio transceivers and their own miniature operating system to tiansmit continuous data to the facility manager. 

A small weather station is illustrated in Figure 3.181. Such stations are usually available in both the cabled and the wireless forms to provide all the information that is needed to control and optimize the various alternative energy processes. These units are usually preprogrammed to provide simple meteorological data, and to perform the complex calculation of ETo (evapo-transpiration). The microprocessor-based systems automatically measure the variables and store the data before transmitting it to a user-supplied remote PC over distances of up to about 10 mi. The units are usually provided with a rechargeable battery pack and a spread spectrum radio transceiver. 

Nodic Company s monohthic RF transceiver chip nRF905 is chose as the wireless communication chip which work in 433/868/915 MHz (SUN Peng 2008), and the transition time between channels is less than 650 ps. It works with 4 modes, and the Shock Burst mode can automatically produce lead code and CRC check code. Current consumption is very low, when transmission power is -10 dBm and the emission current is about 11 mA and receiving current is 12.5 mA. Single-ended whip antenna can be used and the maximum transmission power is lOdBm. In the open area, the furthest transmission distance can reach more than 1 km. 

Radio-Frequency Identification (RFID) Sensors RFID is a technology capable of providing wireless identification of objects. Figure 8 shows a typical RFID system that consists of a transponder (a tag) including an integrated circuit containing an RF circuitry and information to be transmitted, with a transceiver to read the radio frequency and transfer the information to a processing device. 

Wireless communications are made available by telecommunications stations (i.e., transceiver stations or cell towers). There are about 5 million such stations worldwide. By the end of 2011, China itself had about one... 

Finally, communication is realized in a wireless way by means of an integrated wearable textile antenna in combination with a wearable transceiver. Such a kind of wireless communication takes place between the human body and the surrounding environment and is also referred to as body-centric communication. In parallel with textile antennas, this has become a very popular field of research over the last decade [1], with cmcial importance for plenty of applications, ranging from monitoring of vital signs of patients to coordination and monitoring of rescue workers [2], but also in the entertainment sector [3] and in sports [4]. 

A list of various wireless wearable devices is given in Table 7.4. Different wireless technologies have been used in different wearable devices. A prototype of advanced care and alert portable telemedical monitor (AMON) wrist-worn unit is shown in Fig. 7.14 [8]. The system has two major parts a wrist-wom unit and a stationary unit at the telemedicine center. The wrist-wom unit measures physiological parameters and transmits through a Global System for Mobile communication (GSM) network to the stationary unit for data collection and processing by trained medical personnel [8]. The stationary unit is composed of a JAVA server platform and a workstation connected to the GSM transceiver. 

Lilypad XBEE radio transceiver for wireless wearables... 

Figure 5.29 (a) Test and demonstration of breadboard coating health monitor, including wireless communication. Inset shows transceiver unit attached to laptop computer b) Block diagram of the electronics. (Courtesy of Guy D. Davis, DACCO SCI, Inc.)... 

Figure 1 shows an eZ430-Chronos sport watch, a product of Texas Instrument which has been widely used in various wireless applications.Zhou Z. [6] has developed the watch to be used as an electronic door locking device [6]. The watch was programmed to communicate wirelessly with the device attached to the door for the door to be locked and unlocked. This is done by tapping on the watch s 3-axis-accelerometer which is located on the watch s liquid crystal display (LCD). Thisproves that the wireless communication of the watch can be developed as long as the RF transceiver used is suitable for low power wireless applications. 

LabVIEW (computer) The ECG signal is processed by a system developed in LabVIEW to calculate and display the value of heart rate and oxygen saturation. It is also programmed to send the packets of heart rate and oxygen saturation data from the LabVIEW transmitter station via RE module (USB access point), which is wirelessly paired with the existing transceiver in the eZ430-Chronos watch. 

Adafruit s GEMMA miniature wearable PCB Lilypad XBEE radio transceiver for wireless wearables Arduino generic PCBs for Bluetooth, Zigby, and RF applications Inventables offers preprogrammed LED drivers with standard routines Mouser offers the Winbond, PIC chip, and other microprocessors. 

Even in their earliest stages of development, wireless sensor networks include already radio-frequency transceivers soil, water, ion, and VOC sensors global positioning sensors microcontrollers and power sources. See Chap. 14 of second volume for VOC sensors. 

For this level, we developed a platform with ZigBee wireless communication protocol (Carlos, 2007) with a XBEE module (Figure 2). The platform functions as a transceiver. 

Induced attenuation distance is always present in any wireless communication model. For our case study, in the second experiment, we considered an ad-hoc network with IEEE802.15.4 technology and the propagation model exposed in the book ZigBee Wireless Networks and Transceivers (Farahani, 2008). The power loss would be expected in a smooth connection in a building can be expressed by the following equation ... 

Farahani, S. (2008). ZigBee wireless networks and transceivers. London, UK Newnes. 

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