Silicon Samples Arrive For Low-Energy, Single-Mode Bluetooth Solutions

IN TRONDHEIM, NORWAY, Nordic Semiconductor has started shipping silicon samples and development kits of the first member of its Blue Bluetooth lowenergy single-mode solution, the nRF8001, to key customers. Although the Bluetooth low-energy specification is still under development, Nordic is providing a complete beta implementation including host and profiles subsystem. The Blue nRF8001 single-mode slave solution is housed in a 32-pin, 5-x-5-mm QFN package (Fig. 1). It boasts peak current consumption below 15 mA and average current consumption in the microampere range. Depending on the duty cycle, the nRF8001 promises years of battery operating life for coin-cellbattery- powered applications.

Nordic Semiconductor believes that Bluetooth low-energy wireless technology will encourage the deployment of ultra-low-power (ULP) wireless applications by providing a technology that is interoperable. Moreover, Bluetooth low-energy wirelesstechnology- equipped products will be able to communicate with mobile phones and PCs featuring modified Bluetooth transceivers. This technology will operate in the globally accepted 2.4-GHz Industrial, Scientific, and Medical (ISM) band. It features a physical-layer bit rate of 1 Mb/s over a range to 15 m.

The Bluetooth low-energy specification will feature both dual- and single-mode implementations. In dual-mode chips, Bluetooth low-energy functionality is integrated into classic Bluetooth circuitry. As a result, power consumption ultimately depends upon the Bluetooth implementation. It is envisaged that dual-mode chips will feature power consumption of around 75 to 80 percent of conventional Bluetooth chips when operating in Bluetooth low-energy mode.

In contrast, single-mode chips are expected to be highly integrated, compact devices. These chips will typically operate with low duty cycles, entering ultra-low-power idle and sleep modes to wake up periodically for a communication "burst." The simplified Bluetooth low-energy protocol stack features a lightweight link layer (LL) providing ultra-lowpower idle-mode operation, simple device discovery, and reliable point-to-multipoint data transfer with power-save and encryption functionalities. The LL provides a means to schedule Bluetooth low-energy wireless technology traffic between classic Bluetooth transmissions.

Wireless Modules Facilitate Global Communications For The Disabled

IN OXFORDSHIRE, ENGLAND, Low Power Radio Solutions or LPRS has been selected by MRI Services to provide wireless communications for wheelchair users. An initial design project has focused on providing a flexible personal communications system for Toby Hewson, Founder of Just Differenta charity dedicated to making a difference to the lives of disabled and non-disabled people (Fig. 2). Toby, aged 28, has cerebral palsy and cannot walk or speak (except through his pathfinder voice synthesizer). With no hand ability, Toby has to operate the synthesizer with his elbow.

The wheelchair communication system comprises a transmitter located on the wheelchair that sends the output of the Pathfinder synthesizer to a receiver connected into a laptop computer through which Skype communication can be used. The incoming messages are transmitted from a second transmitter fitted to the laptop. They are then sent to the receiver unit on the wheelchair, which is connected to headphones. A mixer in the laptop unit enables Toby to hear what he is sending out as well as what is received. The object of the system is to provide Toby with private communications. Bystanders hear no sound unless intended. The synthesizer can produce Toby's output either in speech for normal conversations or muted for private communication or writing.

At the heart of this system are Circuit Design's WATX/ RX-03-R wireless modules. Typical applications for these modules include industrial monitoring and control systems as well as alarm, security, and communications systems.