Crossbow Announces IMB400 Imote2 Multimedia Board

Building on its popular Imote2 advanced wireless sensor platform, Crossbow Technology announced the new Imote2 Multimedia Board (IMB400), an integrated camera sensor board that simplifies the capture of rich media content for wireless sensor network applications. The IMB400 board adds rich media capabilities to wireless sensor platforms. 

Ralph Kling, Chief Architect for Crossbow Technology said “For the first time visual and audio data can be easily added to wireless sensor applications. This opens up new possibilities for wireless sensor applications, including for example, surveillance, machine vision, object tracking, animal behavior surveys, and elder care monitoring in locations and environments that would otherwise be too costly to observe with traditional monitoring systems.”

The Imote2 Multimedia Board offers a compact, power efficient solution due to its integration of camera, audio and motion detection functionality into one platform. The built-in camera can handle high-quality images with resolutions up to 640x480 pixels and 30 fps, along with audio at sampling rates of up to 48kHz.
Instead of using compute intensive image analysis to detect motion, the IMB400 uses a Passive InfraRed (PIR) sensor to pick up movement, which then activates the camera allowing for its operation as a low power device. These images can subsequently be stored, locally processed and transmitted with accompanying sound.

In addition to the PIR sensor, key subsystems include a color image and video camera chip along with an audio capture and playback CODEC. The board is supported under TinyOS, with future support planned for Linux, SOS and the Microsoft .NET Micro Framework. For more information and to order this exciting new platform, visit Crossbow's site here.

The latest buzz...

If you are looking for ways to expand the capabilities of your Mote deployment, there's a new sensor you should look into - introducing the new BumbleBee Radar! The BumbleBee is a coherent, pulsed Doppler radar offering rich information at a strikingly low price. Introduced in mid-April by The Samraksh Company, the radar ships ready for use with Crossbow's TelosB Motes.

 

Being a pulsed Doppler radar, the BumbleBee measures radial velocity directly. Because it is coherent, you can determine the sign of the velocity and measure the time structure of relative motion very precisely, even for small motions! Range is not measured directly, but in some contexts you can infer range from motion information.

The BumbleBee produces phase information directly resulting in motion information with a resolution of a fraction of a wavelength (i.e. fractions of a centimeter of displacement) which is an order of magnitude finer than if the radar were non-coherent. This information can be received at a rate of ~300 complex (i.e. real and imaginary pairs) samples per second. This capability opens up opportunities for original research and development in diverse signal processing applications.

BumbleBee's sensitivity is optimized for the normal day-to-day movements of people which makes it a compelling choice for monitoring and classifying human activities in commercial and recreational settings. This device could be used to monitor the usage of urban playgrounds, public parks, employer provided recreational facilities, office conference rooms and waiting areas. Quantitative measurements of loitering, underuse, overuse and unauthorized use would provide an improved basis for setting policy, deciding layouts or evaluating security measures.

Other interesting applications include the classification of unique patterns of movement, such as dancing or fighting in nightclubs, exercising or falling in a retirement home, and even working or sitting around on a construction site. Automated detection of various activities would expedite response in abnormal situations and provide positive feedback in normal situations. Not all applications need to center on people of course! For example BumbleBee can be used to do non-contact wobble detection of rotating machinery in industrial settings, monitor livestock activity, even recognize rodents or snakes in remote parts of a building or an urban infrastructure!

The BumbleBee facilitates information rich applications without compromising on Mote-scale constraints. It uses less than 40 mW or total power, has a range of ~10m, and is form factor compatible with Motes. Most importantly, its technology facilitates a new cost paradigm that is more compatible at a system level with the use of large scale Mote networks. At $100 USD/each, price is its most innovative feature! For more information contact info@samraksh.com.

BumbleBee is patented, but a usage license is made available as part of the purchase price for research usage. The Samraksh Company also promises very reasonable terms for small and mid-scale industrial applications. The radar conforms to FCC regulations for operation within the ISM unlicensed band (at 5.8GHz). Non-research applications may need additional FCC certification.

Ice scream, you scream...

Being a native California driver I rarely encounter icy road conditions unless I'm on my way to Tahoe to go snowboarding or skiing. I remember the day we had snow in the Bay Area and everyone ran outside to experience the phenomenon (although it only lasted on the ground for a few moments before melting away). In many parts of the world icy road conditions prevail and the ability to easily monitor and detect the danger is not easy due to the harsh environment. However, the idea of pavement condition monitoring would save many a spinning car and screaming driver from sliding on the ice into the side of the road.

Pavement maintenance is vital for travel safety. By using wireless sensor networks to monitor pavement temperature and moisture presence, icy road conditions can be detected. It is essential to provide warnings of dangerous traffic conditions in real-time. In a study done at University of Oklahoma, researchers determined to investigate a densely distributed sensor network and classify pavement conditions into certain categories - 1) dry 2) wet and 3) frozen.

This project was deployed with the MICA2 Motes from Crossbow while integrating them with various 3rd party sensing devices using the MDA100 prototyping board. The ability to integrate 'alien' sensors to the Mote platform gave the researchers the flexibility they needed to complete the task at hand. The sensors chosen to provide the data included a thermistor to gather temperature readings, a leaf sensor to detect the conductivity of a wet pavement to detect the existence of free moisture and an infrared sensor to detect ice by emitting a near infrared light that is reflected by the ice and detected by the infrared receiver (water is transparent to the receiver).

An integrated sensor and road button structure housed the 3 sensors as shown in the figure above. The top surface of the sensor road button contained the moisture and infrared sensors with the thermistor at the bottom. Due to the low power consumption of the sensors used, these devices were powered by the MICA2 Mote platform. The Mote platform was placed into a protective watertight aluminum casing with upgraded antenna doubling the Motes transmitting range.

When collecting readings from the sensors, the Mote transformed them into digitized data, sent them to the radio and waited until all data was sent before switching to sleep mode. In detail, the processor received sensor readings from the embedded 10-bit Analog-to-Digital Converter (ADC). If the data was taken correctly, the onboard light emitting diodes (or LEDs) lit up to signal the proper functioning of the mote. Analog to digital conversion was performed on the readings, after which the data was integrated into the packet to be transmitted. The default packet format was slightly modified to fit the size and format of the data to be transmitted. The packet was then sent to the radio and transmitted over the network until it reached the base station. The base station was connected to a laptop through a serial port. The data was then collected using a LabVIEW graphical user interface (GUI) developed for this project. Raw data from the serial port was collected, deciphered and displayed by the GUI.

Using the MICA2 Motes to monitor the pavement conditions is a unique application; therefore, the aforementioned features (directly applying time synchronization and embedding a pattern classification algorithm) further distinguish this study from existing research that utilizes Motes in real-world applications. A series of laboratory tests was conducted at the Asphalt Laboratory at the University of Oklahoma using an environmental chamber to study the effect of temperature and moisture on the sensors (and later, the motes). The environmental chamber was used to produce well-controlled temperature and humidity variations. The sensor-road button unit was tested to (1) test the full functionality when all the sensors were combined together, and (2) collect data to aid refinement and further development of the proposed ice detection algorithm proposed in this application. The entire lab test was completed in a four-hour time frame. Note that weather changes in reality could be much slower than this testing rate; thus such a test could be more stringent than a real-world situation.

A series of outdoor tests were conducted as well paying special attention to the packaging and survivability of fragile analog sensors in harsh roadway conditions and how they will be utilized in other applications of intelligent transportation systems (ITS) as well as structural health monitoring. These methods allowed the Mote wireless sensor network to be easily installed and provided a robust solution to environmental factors such as wind and rain. Imagine a day when roads are 'smart', when you are told exactly what conditions to expect before you encounter a patch of ice. It is this concept and future that we envision with the Mote platforms - a smarter safer future that we all can scream for!

Smart Attire - Bringing Technology Into The Closet!

What is smart attire? To some it may be clothes that tell you when they are mismatched, or that figure out how to conform to your body type or inform you that these clothing articles do not belong on your body unless you look like Gisele Bundchen. Smart attire like that would soon get rid of the numerous 'What not to wear' blogs and shows we watch, but unfortunately, that is not what we are talking about today. Smart Attire is the next generation of attire that will embed computing and sensing power in clothes, aiding in the development of novel personal monitoring services such as healthcare for the elderly in the comfort of their own home, safety of people working in dangerous situations such as firefighters, construction workers, etc., personal and medical monitoring for joggers, bicyclists, etc. and even entertainment in offering a personal tourist guide system or for social networking. Smart attire can be useful in many ways to help, benefit and entertain those that use them by personally monitoring their environment and bringing technology into their wardrobe.

The feasibility of embedding clothes with computing devices has come about due to the continued revolution of the decreasing sizes of these devices. This allows the device to be unobtrusive to the wearer. Researchers at the University of Illinois, Urbana-Champaign have developed a Smart Jacket. This piece of clothing is built by weaving MICAz Motes into the lining and padding of a winter jacket. As the size of Motes continue to decrease the goal is to embed these devices in shirts, pants, etc. The jacket prototype developed is capable of monitoring the motion and location information of a person remotely by using accelerometers and a GPS sensor with Crossbow's off-the-shelf sensor hardware such as the MTS310 or MTS420 sensor boards. A typical scenario would be of a person wearing the jacket outdoors while it records the motion and location information in the flash memory of the MICAz Motes. Upon coming into range of the base station, the data collected is uploaded to the PC transparently.

The idea of clothing with sensors and computing devices embedded in them is exciting. The idea is not to create a jacket with gizmos like Inspector Gadget, but to embed sensing into these items. With the development of smart attire that not only integrates technology, but is the technology - it is necessary to develop software to interpret the data collected by the clothing. Hence the development of SATIRE - a software architecture for smart attire. As personal instrumentation and monitoring services that collect and archive the physical activities of a user continue to become more popular, a general software architecture is needed to support the different categories of monitoring services. SATIRE is a personal monitoring service that records the owner's activity and location for subsequent automated uploading and archiving.  It allows users to maintain a private searchable record of their daily activities as measured by motion and location sensors; the goal is to perform this data collection in a manner that is transparent to the user when they come into range of the base access Mote at home. To identify the human activity from accelerometric data is difficult; therefore the SATIRE system uses Hidden Markov Models (HMMs) which is still in development. Future work for this project includes the development of security and privacy policies as well as the identification of more sophisticated activities.

A brief video of the prototype can be seen here:

SATIRE implements remote data logging of daily activities and location information, upload protocols for the raw sensory data collected and the use of sophisticated algorithms to interpret the data and make useful deductions to reconstruct activities from the smart attire. The software architecture developed is flexible and modular for future development of smart attire systems that simplify the introduction of new sensors and new algorithms. To get more information on SATIRE visit the project site here where you can download TinyOS for SATIRE as well as view information on installation and usage of this platform. The future is here - bringing technology into the closet!

Now that's a bright idea!

Presenting the new 'Ping-pong' Illumimote, a light sensing module for the Crossbow Mote platform. Wireless sensor networks have permeated the market in many sectors such as environmental monitoring, asset tracking, industrial automation, etc. But, these devices have exciting applications in arts, multimedia and entertainment as well. Limited sensing quality, fidelity and diversity of the sensor modules have limited their expansion into areas like film, video production and lighting control. To support research and development in these areas, high-fidelity light sensing modules in a compact form factor are required.

Enter the Ping-Pong Illumimote! This device achieves performance comparable to a commercial light intensity meter, while conforming to the size and energy constraints imposed by its application in wireless sensor networks. The board was developed to replace the light sensing capabilities on the MTS310 Mote sensor board whose response time and narrower dynamic range in light intensity capture is unsuitable to many certain applications for light measurement such as media production. The Illumimote features significantly improved SNR due to its adoption of high-end photo sensors, amplification and conversion circuits coupled with active noise suppression, application-tuned filter networks, and a noise-attentive manual layout. Unlike the MTS310, the Illumimote can capture RGB color intensity (for color temperature calculation) and incident light angle (which discerns the angle of ray arrival from the strongest source). The prototype was created by the UCLA NESL & the UCLA Hypermedia Studio, a joint effort between the film makers and the engineers, to apply wireless sensor networks to new purposes in art and entertainment.



The order in which an audience views a film’s sequence of events is remarkably different from the order in which they are produced. Shots are filmed in the order that minimizes cost and makes best use of actors, crew, and locations. Footage captured at these different times must appear the same when shown consecutively, or differences must be controllable if they are required for creative purposes. It is important to monitor and replicate the quality of light (illuminance and color) in each shot, so that footage captured at different times or in different locations doesn’t show unexpected differences, which may not be perceived by the human eye but affect the film stock. The Lord of the Rings trilogy, for example, was filmed over a year and a half of production and required that footage be captured for use in three different movies with vastly differing release dates and schedules. Researchers at UCLA have focused on lighting instrumentation as the first component of their Advanced Technology for Cinematography (ATC) because of its vital role in the creative process of filmmaking. ATC is a joint project of UCLA’s Henry Samueli School of Engineering and Applied Science and the School of Theater, Film and Television. The Illumimote is part of their larger vision to increase flexibility and creative control in media production using sensor networks and other emerging technologies. Deploying networks of tiny sensors adds a data acquisition layer to the film production environment that supports on-set decision making, such as the lighting adjustment described above, as well as post-production and asset management.

Initial work prompted the development of the Illumimote and other high-quality sensor platforms that can be deployed atop Mica Motes, the defacto standard for WSN nodes. The Illumimote is designed to have equal or better performance to the class of commercial light intensity and color temperature meters used in the entertainment, film and video production industries. It supports three different light sensing modalities: incident light intensity, color intensities and incident light angle (the angle of ray arrival from the strongest source), and two situational sensing modalities: attitude and temperature. The device demonstrated significantly faster response time (> 6x) and a much wider dynamic range (> 10x) in light intensity measurement as compared with the standard MTS310 Mote sensor boards. The light-angle estimation results were well correlated with an average error of just 2.63°. The assembled Illumimote with a lumisphere appears in the picture above. The role of the lumisphere is to protect the sensors and to integrate incident light from all directions.

The overall system architecture diagram of the Illumimote appears below. There are eight light sensor channels allocated based on the number of detector circuits required to capture the illumination attribute. For example, the color temperature unit requires three channels—one for each of red, green, and blue luminosity. Signals from the eight light acquisition units and four situational units are multiplexed via the channel selection unit and presented to the ADC for conversion into a 10-bit digital signal. This resultant data is conveyed to the networked and embedded nodes (in this case, MICAz motes) via either the I2C data bus or a direct 16550Acompatible UART link that uses line-level (rail-to-rail) output. The operation of the Illumimote’s units may be controlled directly from the Mote via the I2C bus or locally by an onboard Atmel Atmega48 microprocessor. Employing the local processor relieves the network interface (mote) of any realtime constraints associated with frame-rate-accurate sampling. The local processor also exposes interrupt facilities both to and from the host-processor onboard the mote. When operating in this mode, the continuous I2C bus may be severed and reattached dynamically (hardware is bus-state aware) to create two isolated buses—one local to the Illumimote, and one local to the Mote—as needed. In addition to calibration functions, the embedded temperature sensor can wake a sleeping mote in the event of a dangerous thermal condition (risk of meltdown). On the bottom, Illumimote features a connector that is compatible with standard Mote-type sensor nodes (IRIS, MICA2, MICAz, Cricket etc).



Three embedded software components were developed for the experimental wireless sensing system. First, sensor and sensitivity control software was programmed and downloaded to the Illumimote board. The board was then attached to a MicaZ node that has a 7.37MHz 8-bit microprocessor and a 250kbps ZigBee radio. Secondly, the Illumimote driver and light sensing application were programmed at the MicaZ mote using SOS environment. SOS is an OS for Mote-class wireless sensor networks developed by NESL at UCLA. Finally, at the base station laptop, a Java program was used to monitor and log the light measurements, and a visualization interface was used for real-time debugging and analysis. A GUI visualization interface was developed as shown below to display the status of the Illumimote in real time, that was used for testing, experimenting, and performing demonstrations. The interface was implemented in Java and Processing. This GUI made it easy to test and evaluate the Illumimotes visually and is a step towards designing the interface that could be used by a cinematographer in future.



The Illumimote achieves performance comparable to a commercial light meter and color meter (as used by professional cinematographers) over the ranges tested. It consists of incident light intensity, RGB intensity (for color temperature calculation capability), and incident light angle sensors as well as thermal and attitudinal sensors. Researchers at UCLA characterized its performance and verified its capabilities. The project website hosts the technical data and the Illumimote will soon be commercially available from Atla Labs to allow other researchers access to the technology for their own experimentation. Future work includes further enhancements to the general characteristics of the Illumimote (such as dynamic range), estimation of the vertical incident light angle, and further development of the software tools that support and integrate the Illumimote in support of its deployment on actual productions scheduled for the near future.

Not just a pipe dream!

US water facilities and those around the world are faced with mounting operational and maintenance costs as a result of aging pipeline infrastructures. The ability to monitor and control the infrastructure is no longer a pipe dream but is on its way to becoming reality thanks to wireless sensor networks. PipeNet, is a system designed by researchers at Imperial College in London and CSAIL at MIT in conjunction with Intel Research, to collect hydraulic and acoustic/vibration data at high sampling rates as well as use algorithms for analyzing this data to detect and locate leaks. A study by the EPA (Environmental Protection Agency) estimates that water utilities will need $277 billion over the next 20 years (2003-2023) to install, upgrade, and replace infrastructure. Unfortunately, identifying the high priority areas is a non-trivial task because of the scale and age of the pipeline infrastructures. Failures of large diameter bulk-water transmission pipelines are of greatest concern as these are supply critical systems. When these failures do occur, there are dire consequences including loss of life, severe interruptions in service, degraded fire fighting ability, damage to adjacent infrastructure and buildings, and of course the multi-million dollar repair bills.

PipeNet is a system based on wireless sensor networks which aims to detect, localize and quantify bursts and leaks and other anomalies in water transmission pipelines such as blockages and malfunctioning control valves. The system was based on Intel Motes (the 1st generation of the Imote2 devices available today) to provide remote monitoring in near real-time with support for high data rate time synchronized data collection from multiple locations. This is a significant change from current data acquisition practices of using portable data loggers with a low duty cycle and limited remote monitoring stations that do not have the capability to do local processing or high-bandwidth transmission.

The Motes were responsible for the data collection, local signal processing and relaying of data to the second tier consisting of the Stargate platform that was to relay the data back to the backend server via a GPRS modem. A special sensor board was also designed to interface to the Mote to accommodate the various analog sensors used in PipeNet. The clusters contained pressure sensors and pH monitoring sensors combined with water level monitors and pressure monitors. The mote could be configured to trigger data acquisition on a channel remotely when a monitored channel exceeded some threshold. Acoustic and vibration data analysis was used to detect and locate small leaks which are difficult to identify with hydraulic data. Vibration signals collected showed differences in the mode of wave propagation if a leak was detected. Leaks also manifested themselves in the acoustic signal which propagates uniformly in both directions away from the leak by the escaping water flowing through the rupture in the pipeline.

The Motes communicated from the manhole to the Stargate based gateway deployed on a nearby lamppost. The Stargate, the GPRS modem and 802.11 radio were powered from the power lines at the lamp post. The Intel Mote was connected to the Stargate through its UART interface acting as a bridge between the Stargate and the motes on the pipes. This cluster head was responsible for forming the sensor network, converting the configuration data coming from the Stargate and passing it to the correct sensor node as well as delivering the data collected via the reliable transport protocol to the Stargate where it was converted back into data files. These files were periodically sent to the backend server running in the lab via the GPRS link. The Stargate was equipped with an 802.11 link to facilitate drive-by access for on-site configuration and debugging as well. Data transfer was handled via standard Linux tools, and the data files were then loaded in a Postgres database that stored the individual sensor readings. This gave users the ability to browse these sensor readings by connecting to an Apache Web server running on the server. The web site used Google Maps/Google Earth to allow users to select and browse the sensor locations of interest. Once users selected a sensor location, they could retrieve data corresponding to a user-specified date / time range and sensor type to visualize the data.

Using the leak localization algorithms they developed, the research team was able to localize leaks to within 30 cm. The long term monitoring of pressure and acoustic signals in particular pipes will also facilitate the development of more accurate pattern recognition and classification models in the future. The next revision of the PipeNet system is using the Imote2 platform which integrates many essential components to enable high performance and energy efficient data processing. The XScale processor on the Imote2 has dynamic voltage and frequency scaling capability to allow applications to balance performance and energy needs by selecting speeds between 13 and 624 MHz. In addition, the processor includes a DSP co-processor to accelerate common data analysis primitives (e.g FFT, compression) thereby greatly improving performance and energy efficiency. This performance advantage will allow users to carry out the analysis and data reduction in real-time, thus reducing storage and power. Finally, the Imote2 includes 32 MB of SDRAM and Flash enabling the decoupling of data collection and communication with a richer peripheral support that will provide higher data acquisition rates and improve sensor integration.

PipeNet is the future of pipeline monitoring providing the capability to automatically detect leaks and bursts of water in the transmission pipelines; real-time operation with few false alarms; inexpensive to produce, install, and maintain; high-frequency data collection; the ability to differentiate between sensor and system faults; and a flexible reusable data-flow based programming environment. This system will not only improve our ability to monitor large scale water supply systems, but to conserve our natural resources and use them efficiently.

Motes in Antarctica!

Can you imagine a place where the temperature can get to -82°C? A place without sunlight for half the year. Imagine a frozen desert with no permanent human population - the coldest, driest and windiest continent on earth... It is in this place that research scientists from the Institute of Remote Sensing Applications at the Chinese Academy of Sciences have deployed a wireless sensing system using Crossbow's Mote platforms. Being a resident of sunny California I can barely fathom such an environment. If the temperature drops below 50°F (10°C), I want a cup of hot chocolate and a fire to cuddle in front of. Imagine being in a place where the climate is so harsh - there are no plants or animals. Talk about extreme sensing!

China News reported that the wireless sensor network called the 'Unmanned Wireless Intelligent Snow and Ice Observation System in Extreme Environments' has been successfully set up around the Dome-A area near the South Pole, which is the southernmost point on Earth's surface. Dome-A (Dome Argus) is the highest and possibly coldest place in Antarctica and perhaps the coldest naturally occurring place on Earth. It is the highest ice feature in Antarctica, comprising a dome or eminence of 4.093 m elevation.  The system was co-developed by Crossbow Technology and the Chinese Academy of Science to develop a solution that can consistently work under extreme environmental conditions such as a 4-month polar-night, -82°C temperature lows and an annual average temperature of -55°C. The wireless system deployed by CAS scientists is designed to overcome the low-temperature, high-altitude and soft snow-surface.

The deployed system consists of two base stations and four nodes. Each node is powered by two low-temperature resistant batteries which are expected to last for one year. The communication capability between each node can achieve ranges of up to 1000m. Each node samples environmental data every 15 minutes, including temperature (weather temperature, snow temperature and the snow temperature below 1 meter), humidity, sunlight, and air pressure. The collected data is sent wirelessly to the central base station that collects and sends the data to Beijing every day. Meanwhile, the other remote base station is used to store the data locally to be collected later by an expedition team. The two base stations ensure that no data is lost in the communication.

The Antarctic ice sheet where Dr. Xiao and his scientific expedition team ventured is the highest point on the continent. The group hopes to gather vital information on the environment and observing conditions around Dome-A to determine whether or not it is a viable location to expand the observatories in the region. Dome A claims the best astronomical sky conditions in the world, as it is devoid of clouds and boasting steady air that makes for clear viewing. Imagine...Motes in Antarctica!

Swarm Navigation with TelosB Motes

The concept introduced below provides a highly effective swarm navigation scheme that is of low complexity, robust, and highly scalable. Rather than using a few highly complex and expensive swarm agents to complete a mission, the group at Easysen believe in the advantages of large ultra-low complexity swarms that solve problems reliably through emergent behavior.

EasySen is a start-up company who in conjunction with the University of Notre Dame’s Mobile Sensing Systems (MOSES) Lab, has developed an autonomous sensor swarm that uses TelosB nodes for navigation of swarm agents. The principle is based on Zigbee radio beacon induced potential fields and provides an ultra low cost and complexity solution to mobile sensing for land, sea, and air vehicles. Stereo TelosB receivers and stereo sensor suites (EasySen SBT80 / SBT30-EDU) allow for rather elaborate task execution.

The group at EasySen proposed the use of radio frequency beacons to generate (switched) potential fields for navigation of large numbers of swarm agents. The idea is to use attractive beacons as waypoints and local attractors. Repelling beacons on each agent and waypoint are used to control the density of agents and avoid collisions.  If a certain sequence of waypoints defines a navigation path, then the attractive beacons need to be distinguishable and need to be visited in a certain sequence. (This is easily implemented in form of a finite state machine in each sensor swarm agent.) Repelling beacons are local and do not need to be distinguishable.  Individual sensor swarm agents are equipped with a side-looking stereo receiver with opposite directions of highest sensitivity. A simple difference between the left and the right Receive Signal Strength Intensity (RSSI) allows the agent to detect in which half space (relative to the center length axis of the vehicle) a beacon is located. One can then navigate towards a beacon by always moving towards the receiver side that has produced the stronger RSSI reading. For repelling beacons, one always moves towards the direction of the smaller RSSI signal.

The applications of this paradigm are many and range from environmental clean-up such as oil spill removal to surveillance and protection tasks. A ground vehicle swarm that performs a simple detection task is shown in the video below:

The company also produces readily usable plug-in surveillance sensor suites for the TelosB wireless 802.15.4 platform:

• The Wi-Eye, an ultra-sensitive sensor board that is capable of detecting the IR signature of moving vehicles from as far as hundreds of feet away.
• The SBT80 is an 8-modality sensing platform, ideal for sensor fusion applications.

Both sensor suites (the Wi-Eye and the SBT80) are prime candidates for perimeter security, traffic monitoring, tracking, and occupancy detection tasks, just to name a few. In addition, EasySen also offers SBT30-EDU, a low-price educational prototyping board that interfaces to external signal sources.  Click here for more information on the TelosB Mote platform.

RadMote - Mobile Framework for Radiation Monitoring

I don't know how many times I've watched the Simpsons and seen Homer Simpson sitting in front of his Safety Command Console at the Springfield nuclear power plant snoozing and eating donuts, only to scream and panic while pushing buttons at random when a meltdown seems inevitable. He is the safety inspector and is supposed to keep a close watch to ensure that no accidents occur. Yet, so often we see Homer doze off, leave his post unmanned, or even replace himself for the day with a chicken, a manatee, a homeless man or even a brick to cover for him. He is the lowest ranking person at the plant, yet is tasked with one of the most critical jobs. If only it were so simple...

Nuclear energy generates more energy when compared to other available forms such as thermal, kinetic, etc. It is a power source that is seen in many countries around the world, but its correct and safe operation is essential for its surrounding population. Although Homer Simpson's portrayal of nuclear safety at the plant appears trivial, the exact opposite rings true.  Most nations utilizing nuclear power have special institutions overseeing and regulating nuclear safety. Globally, the International Atomic Energy Agency works for the safe and peaceful use of nuclear science, and in the United States, the Nuclear Regulatory Commission ensures the safety of nuclear plants and materials. Due to the extremely serious repercussions that a nuclear accident could provoke, safety measures are especially important in these power plants.

Researchers at Malaga University in Spain have developed a prototype system using Motes to monitor the environmental conditions around and inside a nuclear power plant, with a specific focus on radiation levels. Sensor nodes equipped with radiation sensors are to be deployed in fixed positions throughout the plant. The staff at the plant is to be equipped with mobile devices with higher capabilities such as PDAs to monitor radiation levels and other conditions. The system enables communication between PDAs which form a mobile ad-hoc wireless network and allows workers to monitor remote conditions in the plant. The motes deployed in the environment communicate wirelessly to gather and report information about physical phenomena that can be used to improve safety measures.

To set up the prototype system, researchers used Crossbow's popular MICAz Mote platform along with the MDA300/100 data acquisition boards which would allow the addition of a radiation sensor to the network. The Stargate gateway was used as a sink node to interconnect the Motes using the 802.15.4/ZigBee compliant standard and PDAs using the Wi-Fi (802.11b) standard. The high level of communication was done with the HP iPAQ hw6500 Mobile Messenger which provides GSM connectivity. The sensor nodes were deployed in fixed positions. Environmental sensed data flows through the network to the sink nodes (Stargate gateways). The PDAs get connected to any of the reachable gateways in order to subscribe to the service of receiving gathered data. PDAs are also connected with each other in an ad-hoc manner, this way if it is far from the wireless sensor network; it can ask for the networks conditions from its neighbors. The data is then displayed in a datagrid component on the PDA as the front-end application. Using sophisticated routing algorithms and connection protocols, the system is able to interconnect the wireless sensor network and mobile ad-hoc wireless network to provide the information quickly and easily to the workers at the plant.

The system's basic features are to display data on the PDAs in real-time from environmental conditions, to display the relative position of the sensor nodes either via localization algorithms or noting their fixed position, alarm generation and propagation to detect risk situations, and to interact with the central server to provide data to the PDA and database. The increased safety measures that a wireless sensor network can provide to monitor the environmental conditions in situations where security, reliability and autonomy are paramount would not only aid in detecting accidents but prevent them from ever occurring. Wouldn't Homer be relieved? D'oh!

Intelligent Wireless Asset Tracking of Packaged Gases

Asset tracking is basically defined as a system that enables one to track an asset using several technologies. Asset tracking is an essential part of many industries, in particular, those concerned with logistics, purchasing and manufacturing.

Gas cylinders are used in many different situations, such as in research, in industry, in healthcare, and even in the home. They are tanks or pressure vessels used to store gases at high pressure. The transportation and storage of gas cylinders is regulated by most governments. Due to the demand  for monitoring and tracking in such a wide variety of circumstances, there is an inevitable ambition of gas suppliers to improve the efficiency of their business. A prototype system developed at Liverpool John Moores University addresses a new idea to use Motes to provide a tracking system that would improve efficiency while also integrating sensors in order to monitor gas cylinders from a safety perspective.

The aim of the prototype system was to discover whether or not communication between motes was possible and reasonably reliable despite signal attenuation which would be caused by the metallic surroundings. This simulated asset tracking environment contained caged gas cylinders which were stored outdoors. Each of the cyclers used during testing has a MICA2 Mote securely attached to its collar via a nylon cable tie with each mote arranged randomly to create non-line of sight (NLOS) conditions. The antennas were in various orientations and touching the metal gas cylinders. The situation was setup as a worst case scenario for RF communications in this application.

The base gateway received the data from the network and would communicate the information to the computer which had stored the network addresses or node IDs of the motes which were arbitrarily associated with a particular type of gas (e.g. Nitrogen, Oxygen, etc.). In order to ensure reliable communication between the base station and the motes attached to the gas cylinders outside, an intermediate relay node was used - it was placed outdoors with a brick walled building between. The prototype system was successful in collecting data within such an environment. Users were able to determine which tags were active at any one time, communicate with individual tags via their unique node ID in order to trigger an event such as sounding the buzzer on board. This two-way communication allowed tags to be identified and provide sensory data.

This idea for an automated gas storage facility is to monitor the gas cylinders when they are in motion. The facility could be unmanned and treated as a location where the gas cylinders were picked up and dropped off. When entering the facility, motes could be interrogated to identify themselves (i.e. their contents, from where they were being returned, etc.). Each mote would not need to rely on a specific reader to send its data, but could communicate the data over the multi-hop mesh network. This would allow data on what the cylinders needed to be filled with, when, or for who to be sent quickly and efficiently to the warehouse. This type of data would prove advantageous to the end users as well to automatically trigger an order of new stock of the particular gas that had been used, etc. Primarily, It also helps with safety issues if interfacing some type of pressure sensor to monitor the contents and prevent a dangerous or explosive situation. Accelerometers could be used to determine the orientation of the cylinder and worn the user if it is stored incorrectly. The flexibility of the mote platform to interface with various sensors is greatly useful for such an application.

This capability to monitor and track assets intelligently will enable a more reliable and safe environment especially for critical applications such as the storage and transportation of packaged gases!