RADIO COMMUNICATIONS
Bluetooth wireless technology is a simple two-way wireless (radio) protocol that allows different electronic instruments to talk to each other without using cables or infrared. “Bluetooth” is the codename for a technology specification for low-cost, low-power, short-range radio links between mobile PCs, PDAs, mobile phones, and electronic instruments. Bluetooth wireless technology can be used to collect data from remote sites or as a main link to a hub site, with a private radio system used to extend out to other nearby telemetry modem.
Examples of environmental monitoring applications using Bluetooth wireless technology: While users may still visit a water monitoring location, they may want to communicate via their computer or PDA with out direct cable access to the data collection platform. Or the user my want to install another telemetry modem within 100 meters of the data collection platform. These are a good application for a Bluetooth wireless enabled data loggers, such as provided by Stevens. Also, using Stevens RS232 or RS485 Serial Port Adapter using Bluetooth wireless technology makes any data logger Bluetooth enabled.
Bluetooth and Wi-Fi. A wireless network consists of several access points for connecting computers, PDAs, or other electronic instruments with wireless network cards in a nearby area to a network or to get access to the Internet. There are two main standards for wireless networking, Bluetooth techology and IEEE 802.11 (a.k.a. Wi-Fi for wireless fidelity). Both Bluetooth technology and IEEE 802.11 networks can coincide in the same environment, but each have different approaches to connectivity.
Bluetooth Technology Overview
Bluetooth wireless technololgy can be used in any electronic device: computers, data loggers, printers, fax machines, GPS, cameras, etc. Bluetooth technology consists of a microchip and software within the chip called a link controller that works to identify other Bluetooth wireless devices to send and receive data. It can send both voice and data. It operates at 2.4 GHz radio spectrum and is designed for a small proximity. A Bluetooth radio is certified to three different class standards. Each class provides different power output, thereby establishing different communication ranges. The following are the typical communication range for each class:
Class 1: 100 meters
Class 2: 10 meters
Class 3: 1 meter
The Bluetooth Special Interest Group’s (SIG) operations and industry certification standards permit for easy connectivity between any Bluetooth wireless enabled devices. The robust Bluetooth technology capabilities enable many possibilities for simple, low power and low cost abilities to handle both data and voice transmissions. As it has in the personal connectivity market, it is also revolutionizing the data collection industry, providing freedom from cable and wire connections to data loggers cable connections.
Devices connect with each other by automatically examining each other's profiles that are coded into the devices. Profiles contain information about the device, what it can communicate with, and what it is used for. A connection of two or more Bluetooth wireless devices is called piconet. If there are several devices near each other the radio signals could have some interference but are usually very unnoticeable. Wireless networks using Bluetooth technology are usually not very large.
Bluetooth Wireless Technology Operations
Incorporating a RS232 Adapter using Bluetooth technology with a data logger, the RS232Adapter remains connected to the data logger’s RS232 serial port. When the user’s Bluetooth wireless enabled computer is within the Bluetooth enabled data logger’s class range, the computer is instructed to search for Bluetooth wireless devices. The computer may find one or multiple Bluetooth enabled devices. The name and/or device address of all Bluetooth enabled devices discovered will appear on the computer screen. The user simply selects which Bluetooth enabled device they want to communicate with and connection is established.
Each Bluetooth radio has a unique device address and the user can set up a user defined device name for the device address. For security, Stevens RS232/RS486 Adapter with Bluetooth wireless technology can also be configured with password protection.
Application Example
When combined with data loggers through an RS232/RS485 series port adapter with an external antenna, Bluetooth wireless technology offers many other advantages. It eliminates the need to open enclosures that house the data logger, in order to establish communications. It can be used to collect data from a remote site or be employed as the link from the data collection platform to a nearby telemetry modem whose location is better positioned for RF performance. In monitoring applications, data logger communications also can be established without users leaving their vehicles.
One example is the Stevens Water Monitoring Systems, Inc. class 1 RS232 / RS 485 Serial Port Adapter that enables a wireless link between any data logger with a serial port and another Bluetooth enabled computer, PDA, telemetry modem or device.
Advantages for Bluetooth wireless Communications
Lower power: Bluetooth enabled transceivers are lower in power consumption than other alternative wireless products used to replace cables and wires connecting portable and/or fixed electronic devices.
Lower hardware costs: Bluetooth enabled radios are lower in costs than alternative wireless products. Many PDA’s, computers and other electronic instruments are now Bluetooth enabled. Therefore, configuring your communication equipment with an external radio system may not be necessary. Inexpensive adapters are available to easily make various electronic instruments Bluetooth enabled via the USB, RS232 or RS485 serial port. For example, if your computer is Bluetooth enable, you would only need to purchase one RS232 Adapter to establish a wirelessly link with a data logger.
Simply connectivity: Connections are established dynamically and automatically only when Bluetooth enabled devices enter and leave the Bluetooth enabled radio’s transceiver range.
Easy interface with other telemetry modems: Bluetooth enabled radio’s can interface with other nearby radio, satellite or cell modems for long-range communications in areas that the RF signal is impeded, such as a sewer manhole, valley, or structural interference.
Industry / international standard communications: Bluetooth is a registered trademark owned by the Bluetooth Special Interest Group (SIG), Inc., which established the industry / international standards and operating consistancy for all Bluetooth wireless communications.
No communications cost. Because Bluetooth technology uses the 2.4 GHz frequency band, this is spread spectrum and the communications are free.
Disadvantages of Bluetooth wireless Communications
Communication range considerations: While all Bluetooth enabled radios can communicate regardless of the radio’s class range, the Bluetooth communication ranges are typically limited to the highest-class radio being used. Therefore, if an adapter with Bluetooth technology on the data logger is Class 1 – which is a 100-meter communication range, and the Bluetooth enabled computer is a Class 2 radio – which is a 10-meter communication range, the user would likely be limited to the 10-meter communication range.
Designed for only short-range communications. Communications are designed for short-range communications – certified to no more than 100 meters.
Antenna management limitations. Many Bluetooth enabled devices or adapters come with antennas embedded into the circuit board design. Therefore, improving communication range via adjusting or installing a higher gain antenna for such devices is not possible.
Potential USB Adapter Conflicts. External USB Bluetooth enabling adapters requires the user to load unique drivers to the computer. Installing multiple wireless communication drivers on one computer may cause communication conflicts with the computer.
Radio repeaters under development. Currently in development is the ability to integrate Bluetooth radio repeaters to increase the ranges of transmission.
"The Bluetooth® word mark and logos are owned by the Bluetooth SIG, Inc. and any use of such marks by Stevens Water Monitoring Systems, Inc. is under license. Other trademarks and trade names are those of their respective owners."