Wireless technology is spreading sensor applications to just about everywhere in the world, and the exhibitors at Sensors Expo & Conference 2008, held June 9-11 in Rosemont, Ill., are all ready to take advantage of these global opportunities. Designers now include wireless sensors in automobiles, trains, and airplanes to monitor performance and energy use. Architects use them in buildings, bridges, tunnels, pipelines, and power lines to keep tabs on their structural health. Hospitals use wireless sensors as well for treatment and record keeping.
Micro Strain, Green Peak Technologies, Newtrax Technologies, and Smart Structures Inc. announced their latest advances in wireless transceivers during the show. Optical sensor manufacturers like QPS Photronics Inc. and OZ Optics Ltd., whose devices are used in wireless sensor networks, also revealed new products. Furthermore, many companies said they are seeking a greener technology approach through energy conservation.
Energy scavenging was a key topic at the conference, with many techniques promoted during panels and on the exhibit floor. Many of these presentations examined energy savings via the use of solar energy, wind energy, thermal energy sources like thermopiles, mechanical elements, electrodynamic sources, piezoresistive devices, electrostatic devices, and electromagnetic effects.
GreenPeak Technologies showed off its Emerald GP500C “autonomous” transceiver. According to the company, the GP500C is the only extremely low-power chip that complies with the IEEE 802.15.4 standard, also known as ZigBee. “This chip consumes just 100 nA in the sleep mode (versus 1 µA typically for other devices) and requires 65% less energy consumption for packet processing compared to what’s on the market,” said Cees Links, GreenPeak CEO.
Khanh Tuan Le, strategic marketing manager for Texas Instruments, said that TI’s highly integrated CC2340 system-on-a-chip (SoC) IC can simplify ZigBee design. This chip includes a timer, interface ports, memory, a microcontroller, a transceiver, a real-time clock, an analog-to-digital converter (ADC), and a universal asynchronous receiver/transmitter (UART). The CC2480 SoC, which is the first member of TI’s Z-Accel family of ZigBee-certified network processors, also provides full ZigBee functionality while minimizing development effort.
Cymbet Corp. showed off its EnerChip thin-film semiconductor battery module. The 5-by 5-mm surface-mount device is available in two versions—3.8 V at 50 µAH and 3.8 V at 12 µAH. The company also teamed up with ANT, a supplier of wireless sensor networks for ultra-low-power networking applications in sports, wellness, home, and industrial automation, all demonstrated on the show floor, to exhibit energy-harvesting approaches in sensor networks.
Digi International showed off its tiny XBee battery-powered sensors for wireless networks on the exhibit floor as well as in a technical presentation (Fig. 1). Designed for easy drop-in integration into ZigBee systems, “they’re half the size of a deck of cards and feature long battery life,” said Larry Kraft, Digi’s senior vice president of global sales and marketing.
Microchip Technology was prominent on the show floor with its 2.4-GHz ZigBee FCC-certified RF surface-mountable transceiver module (Fig. 2). The MRF24J40MA can be used with hundreds of 8-, 16-, and 32-bit Microchip PIC microcontrollers. It is supported by Microchip’s PICDEM Z demo kit and the Zena wireless network analyzer, as well as by the company’s free ZigBee MiWi and MiWi peer-to-peer software protocol stacks, which were introduced with the transceiver at the show.
Wireless sensor networks depend on reliability and their ability to robustly overcome multiple sources of interference. Recognizing this, Virtual Extension exhibited its highly advanced wireless Mesh-RS network. Based on the company’s patented Diversity Path Mesh, all of the nodes in the network’s advanced flooding Mesh technology act as relays, transmitting other units’ data to create a modular solution with a practical unlimited number of nodes and unlimited area coverage. A built-in secured message delivery feature eliminates the need for routing, configuration, and healing.
ArchRock’s PhyNet also makes low-power mesh networking for wireless sensor networks easier. OEMs and systems integrators can seamlessly embed this version of the company’s IP network technology into their wireless networks and sensing devices, with complete access and control through familiar Web service environments.
To satisfy regional alternatives to wireless 2.4-GHz transmissions, where channel characteristics of frequencies below 2.4 GHz provide performance advantages in certain environments, MeshNetics showed off a 900-MHz ZigBee Pro module (Fig. 3). The module is designed for the 915-MHz U.S. instrumentation, scientific, and medical (ISM) band and the European 868-MHz band. It features exceptional sensitivity of –110 dBm and 11 dBm of output power for a line-of-sight range up to 6000 m, or more than 3.7 miles. It also draws a mere 26 mA in the transmit mode, 11 mA in the receive mode, and 6 µA in the sleep mode.