08 January 2001
Bluetooth: Is anyone going to sink their teeth in?
At ISA/EXPO 2000 in New Orleans, one of the must-sees was a spinning, jumping, flipping, martial arts expert in the Crossbow booth. His body was covered with a mesh of strain and temperature sensors all using wireless connections back to PCs and PalmPilots running data logging software. The intent was to demonstrate the viability of Bluetooth as a wireless sensor standard.
What exactly is Bluetooth? Well, it's a technology standard for very small wireless LANs. Bluetooth systems talk to one another via a 2.4-gigahertz frequency radio embedded on a chip. That's a step up from infrared technology, which requires devices to be in the line of sight of a network base station in order to establish a connection.
Bluetooth is considerably cheaper than other spread-spectrum technologies, such as IEEE 802.11 (aka wireless Ethernet). It also has the backing of some heavy hitters in the communications world, including IBM, Intel, and Toshiba, along with cell phone makers Nokia and Ericsson.
Like many communications protocols, Bluetooth is primarily targeted at the commercial market, particularly the handheld personal digital assistant/cell phone user. Bluetooth proponents claim it will rid corporate campuses, hotels, and airports of wires now needed to accommodate mobile workers. Industrial Bluetooth proponents hope it will do the same for our plant floors.
However, it's certainly not going to rid our industrial plants completely of wires. Its longest operating distance is 100 meters, and most devices developed to date can operate only over 30 meters. But what it does is allow the run from the device to the junction box to be avoided.
As a result, the typical Bluetooth industrial model is to run copper or fiber to Bluetooth transmitters throughout the plant floor and then run Bluetooth for the last 30 meters out to the device. This makes sense because the bulk of the cost in wiring field devices is the portion of the run between the junction box and the actual device.
For example, a Bluetooth factory could have transmitters blanketing the floor. Then when a new measurement was required - say, a motor bearing temperature - maintenance would only have to install a Bluetooth-capable sensor. Of course, this doesn't speak to how to power the sensor, something Bluetooth proponents haven't addressed.
But Bluetooth's biggest problem may not be on the plant floor. Speakers at several commercial conferences (such as Red Herring magazine's NDA Conference) have started to question whether Bluetooth is really viable in the commercial market.
Michel Burger, director of innovation at Web integrator Sapient, pointed out that most consumers aren't using infrared technology to "beam" business cards to one another or synchronize information on different machines, even though it's built in to most new cell phones and PCs.
"Everybody has it, and nobody's using it," he said. "That could be a hint about Bluetooth." If Bluetooth doesn't catch on in the commercial market, it will be a big struggle to catch on in the industrial sector.
-Eric Byres, British Columbia Institute of Technology