Extensible Sensor Platform
|
Imagine a small sensor that monitors your heartbeat and notifies your doctor in case your heart fails. The low-powered, long-lasting, single-chip sensor sends your heartrate data using SDR, a radio device whose function is not fixed in hardware, but can be programmed by software. The sensor also estimates your location through a built-in GPS receiver and transmits that to the hospital over the existing Radio Frequency (RF) communication infrastructure. If you are at home, the sensor can communicate directly with your cordless phone, instructing it to call the hospital. Or, if you are at work, it can send a Internet message to the hospital through company's wireless network. You're even monitored when driving, as the sensor can establish a connection with your Bluetooth-enabled cell phone and instruct it to call the hospital.
When none of these devices are available nearby, the heart sensor can monitor the RF environment and determine if any other RF communication channels are available, such as cell phone towers, police radios, or even someone's Walkie Talkie. It will use these communication channels to send out an emergency message about your heart failure, or any other health-threatening condition that can be monitored with a sensor.
ESP with software-defined radio is the enabling technology for this sort of application. With conventional technology, multiple RF communication devices would have to be implemented as separate pieces of hardware, which would make the device big, heavy, and power-hungry. However, using ESP/SDR technology, a single programmable chip can be automatically re-programmed very quickly to act like a cordless phone, GPS receiver, WiFi card, cell phone, police radio, or any other RF device.
These tiny ESP sensors equipped with SDR could also be deployed to gather data for climate research or monitor pollution in the atmosphere. In the realm of biological research, they could be attached to animals to gain insight into their environment, habits, and health.
In applications where the ESP might wander far from its home base, the sensor platform can use its SDR to communicate in ways normal sensors cannot. The ESP would start by configuring its SDR as a global positioning satellite receiver in order to pinpoint its location. Following that, the ESP would use its SDR to determine the available radio receivers in its area. Then it would adapt to the available receivers, reconfiguring its SDR as a cellular telephone if there is a tower nearby or as an amateur packet radio if there is a helpful operator in the neighborhood. Once the sensor's SDR has adapted to match the available radio receiver, the sensor will then use the SDR to send its collected data back to a central repository for further processing.
Standard sensor interfaces in the ESP
To enhance its applicability, the ESP utilizes two standard sensor interfaces so that commercially available sensors may be used in a "plug and play" manner: I2C and IEEE 1451.4. The I2C is a simple and ubiquitous commercial standard, defined and maintained by Phillips Semiconductors. I2C is a well-understood, time-tested, sensor communication bus adopted by many sensor manufacturers. Additionally, ESP supports the newly minted IEEE 1451.4 interface.
More about SDR
Software-defined radio refers to a radio device whose function is not fixed in hardware, but rather can be programmed by software using digital signal processing techniques. The analog portions of the software-defined radio are kept to a minimum, allowing the radio to become a cellular telephone, a GPS receiver, an amateur packet radio, or any other sort of radio transmitting or receiving device. Three excellent starting points for further information on radio are:
An ideal SDR can operate in any radio frequency band, limited only by national regulatory agencies and the characteristics of its RF "front-end" analog hardware and antenna. The ESP's current approach to the front-end analog hardware is to support a common Intermediate Frequency (IF) and design RF hardware to fit between the antenna and the common IF. Dr. Jennifer Bernhard of the University of Illinois at Urbana-Champaign Electrical and Computer Engineering department is leading an effort to design a antenna for the ESP that would cover a wide band from 50MHz-2.4GHz, wider than any antenna commercially available today.
In summary, the ESP will function as other sensor platforms with the additional benefits of a plug-and-play sensor interface and the added communication capabilities provided by ESP, which allow ESP access to a wider range wireless data communications domain than is available to standard sensor platforms.
ESP in the News
09.21.04 Giving Sensors an Edge
ESP Staff
Donna Cox, PI and visualization
cox@ncsa.uiuc.edu
Matt Hall, visualization and software
mahall@ncsa.uiuc.edu
Volodymyr Kindratenko, system architecture and software
kindr@ncsa.uiuc.edu
Meenal Pant, software
mpant@ncsa.uiuc.edu
David Pointer, technical lead
pointer@ncsa.uiuc.edu
Von Welch, system architecture and security
vwelch@ncsa.uiuc.edu
Paul Zawada, RF hardware
zawada@ncsa.uiuc.edu